WO2014147755A1 - Power converter - Google Patents
Power converter Download PDFInfo
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- WO2014147755A1 WO2014147755A1 PCT/JP2013/057871 JP2013057871W WO2014147755A1 WO 2014147755 A1 WO2014147755 A1 WO 2014147755A1 JP 2013057871 W JP2013057871 W JP 2013057871W WO 2014147755 A1 WO2014147755 A1 WO 2014147755A1
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- snubber
- power converter
- snubber capacitor
- capacitor
- sic
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
- H02M1/34—Snubber circuits
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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
- H02M7/003—Constructional details, e.g. physical layout, assembly, wiring or busbar connections
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
- H02M1/34—Snubber circuits
- H02M1/348—Passive dissipative snubbers
Definitions
- the present invention relates to a power converter.
- Patent Document 1 As a power converter having a fuse, for example, there is one known in Patent Document 1 below.
- Patent Document 1 a high-voltage film capacitor that is connected in parallel to a switching element group that is connected in a predetermined manner and absorbs a high-frequency current ripple due to switching, and a switching element group that is connected in parallel via a fuse.
- the structure which comprises the electrolytic capacitor group which suppresses the pulsation resulting from a frequency is disclosed.
- SiC silicon carbide
- the present invention has been made in view of the above, and protects a power module by suppressing the influence of a short-circuit surge voltage even when a SiC-SW element is applied to a power converter having a fuse.
- An object of the present invention is to provide a power converter that can be used.
- the present invention provides overcurrent protection for each of the high potential side DC line and the low potential side DC line between the smoothing capacitor and the SiC power module constituting the inverter circuit.
- a power converter provided with an element, a first snubber capacitor connected to a terminal portion of the SiC power module, the high potential side DC line and the low potential between the overcurrent protection element and the inverter circuit
- a second snubber capacitor connected to the side DC line, wherein the second snubber capacitor is more than a wiring inductance component between the connection position and the connection position of the first snubber capacitor.
- FIG. 1 is a diagram illustrating a configuration of a power converter according to Embodiment 1.
- FIG. FIG. 2 is a top view showing a structural arrangement example of the power converter according to the first embodiment.
- FIG. 3 is a diagram illustrating an equivalent circuit of a main part of the power converter according to the first embodiment.
- FIG. 4 is a diagram showing an example of a surge voltage waveform generated in the SiC-MOSFET.
- FIG. 5 is a diagram illustrating an equivalent circuit of a main part of the power converter according to the second embodiment.
- FIG. 6 is a diagram illustrating an equivalent circuit of a main part of the power converter according to the third embodiment.
- FIG. 7 is a diagram illustrating a configuration of the power converter according to the first embodiment.
- FIG. 1 is a circuit diagram showing a configuration of a power converter according to Embodiment 1.
- the power converter according to the first embodiment includes a smoothing capacitor connected between a high potential (P potential) side DC line 10a and a low potential (N potential) side DC line 10b.
- an electrolytic capacitor 11 As an electrolytic capacitor 11, an inverter circuit 12 having a power module 14 (14 a, 14 b, 14 c) and converting DC power into AC power, and a DC DC so as to be interposed between the electrolytic capacitor 11 and the inverter circuit 12.
- a fuse 13 (13a, 13b) as an overcurrent protection element inserted between the lines 10a, 10b and a first connected in parallel to each terminal portion 8a, 8b in the power module 14 (14a, 14b, 14c)
- the high potential side in the inverter circuit 12 Electrical connection between the terminal portion 9a (terminal portion of the fuse 13a inserted in the high potential side direct current (DC) line 10a) and the low potential side direct current portion in the inverter circuit 12 used for electrical connection with the direct current portion
- a second snubber capacitor 19 connected between the terminal portion 9b used for connection (the terminal portion of the fuse 13b inserted in the DC line 10b on the low potential side).
- the power modules 14 (14a, 14b, 14c) provided in the inverter circuit 12 are connected in parallel to form a three-phase inverter circuit.
- the power module 14a includes, for example, an SW element (that is, a SiC Schottky-Barrier Diode (SiC-SBD) 16) connected to the SiC-MOSFET 15 and the SiC-MOSFET 15 in antiparallel. SiC-SW element), and a circuit in which two sets of the SiC-SW elements are connected in series is configured.
- a circuit in which two sets of SiC-SW elements are connected in series is referred to as an “arm”.
- the other power modules 14b and 14c are similarly configured.
- the illustrated inverter circuit 12 is a three-phase inverter circuit in which three arms are connected in parallel, and a motor 50 connected to a cable 60 drawn from a series connection point of SiC-SW elements in each power module.
- a three-phase motor for example, a synchronous motor, an induction motor, etc.
- FIG. 1 illustrates a three-phase inverter circuit, a number of arms corresponding to the required number of phases may be provided.
- FIG. 1 illustrates a configuration in which two sets of SW elements connected in series are accommodated in a module, but an inverter circuit 12 is configured by accommodating six sets of SiC-SW elements in one module.
- the inverter circuit 12 may be configured by six modules in which one set of SiC-SW elements is accommodated in one module.
- FIG. 2 is a diagram illustrating a structural arrangement example of the power converter according to the first embodiment, and is a top view of the inside of the power converter as viewed from above. 2, the electrolytic capacitor 11 itself shown in FIG. 1 is not shown, and a pair of positive and negative electrolytic capacitor connection terminals 21 is shown.
- the electrolytic capacitor 11 includes an electrolytic capacitor P terminal 24a electrically connected to the P potential copper bus bar 22a visible on the upper surface, and an electrolytic capacitor N terminal 24b electrically connected to the N potential copper bus bar 22b on the back surface side. Connected between.
- the power module 14 (14a, 14b, 14c) includes a P terminal 25a electrically connected to the P potential copper bus bar 23a visible on the upper surface and an N terminal electrically connected to the N potential copper bus bar 23b on the back surface side. 25b.
- the output terminal 29 is a terminal provided at a series connection point between SiC-SW elements. The output terminal 29 is electrically connected to the cable 60 (see FIG. 1).
- region shown with the hatching of the broken line shows the hollow part in P electric potential copper bus bar 22a, 23a.
- the P potential copper bus bars 22a and 23a and the N potential copper bus bars 22b and 23b are arranged in close proximity to each other with an insulator interposed between the copper bus bars, and the inductance component of the PN line by each copper bus bar is made as small as possible.
- the surge voltage when the SW element is short-circuited (hereinafter referred to as “short-circuit surge voltage”) is reduced.
- the fuse 13 (13a, 13b) is provided when the capacity of the power converter is large. When the capacity of the power converter is large, a large amount of energy is also stored in the electrolytic capacitor 11. Therefore, in order to avoid the accidental expansion due to the large energy of the electrolytic capacitor 11 when a short circuit accident of the power module 14 occurs, the fuse 13 Is required.
- P potential copper bus bar 22a, P potential copper bus bar 23b, N potential copper bus bar 22b, and N potential copper bus bar 23b are integrated with each other. It is usually done.
- a first snubber capacitor 18 (18a, 18b, 18c) is connected between a P potential terminal and an N potential terminal (not shown) of the power module 14 (14a, 14b, 14c).
- 2 shows an arrangement example in which two first snubber capacitors 18 are arranged in parallel for each power module 14, and 5 fuses 13 are provided for each P potential and N potential in order to improve the reliability of the power converter.
- N potential side is not shown
- the SiC-MOSFET 15 has a high switching speed, and a surge voltage generated due to the wiring inductance at the time of a short circuit failure becomes very large.
- the opposing portion of the PN copper bus bar is broken at the fuse 13 portion, and the inductance component of the fuse 13 itself is also added.
- the inductance component between the power module 14 increases. For this reason, due to these two factors, the surge voltage generated in the power module 14 becomes large and may exceed the maximum rating, and some countermeasure is required.
- FIG. 3 is a diagram showing an equivalent circuit of a main part of the power converter according to the first embodiment.
- Ls is a wiring inductance component inside the power module
- Lpn1 is a wiring inductance component due to the PN copper bus bar (23a, 23b)
- Lpn2 is a wiring inductance component due to the PN copper bus bar (22a, 22b)
- a fuse 13 and the inductance component is shown with a parasitic inductance component and a parasitic resistance component added to the original capacitance component.
- the SiC-MOSFET 15 is indicated by a switch symbol
- the SiC-SBD 16 is indicated by a capacitance component and a resistance component.
- Other elements are denoted by the same reference numerals as those in FIG. 1 or FIG.
- FIG. 4 is an example of a surge voltage waveform generated in the SiC-MOSFET 15.
- FIG. 4 shows a waveform when the second snubber capacitor 19 is not provided in the configuration of the first embodiment.
- the horizontal axis represents time
- the vertical axis represents voltage
- the waveform K1 represents the gate-source voltage (Vgs) generated in the SiC-MOSFET
- the waveform K2 represents the drain-source voltage generated in the SiC-MOSFET 15. (Vds).
- the surge voltage generated in the SiC-SW element has a first wave (a component rising in the vertical axis direction) and a second wave (portion surrounded by an ellipse) that comes after the first wave.
- the first wave is generated mainly by the relationship between Ls and the first snubber capacitor 18, and the second wave is generated mainly by the relationship between Lpn (the sum of Lpn1 and Lpn2) and the first snubber capacitor 18. . Therefore, as a countermeasure against the first wave, it is preferable that the parasitic inductance and resistance of the first snubber capacitor 18 are small. In general, the smaller the capacitance of the capacitor, the smaller the parasitic inductance component and the parasitic resistance component.
- the capacity of the first snubber capacitor 18 must be large. This is because not only Ls but also Lpn is added to the inductance component caused by the second wave. In addition, if Lpn can be reduced, a special measure in consideration of the second wave is unnecessary. However, it is difficult to reduce Lpn. The reason is the following two points. The first reason is that the power converter assumed in the first embodiment is a power converter that requires the fuse 13, and it is difficult to reduce the inductance component of the fuse itself.
- the second reason is that even if a laminated bus bar having a very small inductance component is used as the PN bus bar, the laminated bus bar is divided at the fuse 13 and the opposing property of the laminated bus bar is broken by the fuse 13. This is because there is a limit to minimizing the inductance component.
- FIG. 2 discloses an example in which six capacitors are arranged as the second snubber capacitor 19 using the empty space of the five fuses 13a provided on the upper surface side (P potential side).
- the number is not limited to six.
- the terminals 9a and 9b of the fuse 13 to which the second snubber capacitor 19 is connected are terminals on the electrolytic capacitor 11 side (that is, electrical connection with the electrolytic capacitor 11).
- Terminal 9a, 9b on the inverter circuit 12 side that is, a terminal for electrical connection with the inverter circuit 12.
- the capacitance value of the first snubber capacitor 18 is preferably smaller than the capacitance value of the second snubber capacitor 19. If a capacitor having a small capacitance value is selected as the first snubber capacitor 18, a capacitor having a small parasitic inductance component and parasitic resistance component is necessarily selected. As a result, the first snubber capacitor capacity optimum for the first wave countermeasure is set.
- the second wave countermeasure is negatively affected, but there is no problem because the second snubber capacitor 19 exists.
- the capacitance value of the second snubber capacitor 19 is increased, the second snubber capacitor 19 effectively acts against the second wave.
- the first snubber capacitor capacity and the added second snubber capacitor capacity are in a parallel connection relationship, the total value of the first and second snubber capacitor capacities effectively acts as a countermeasure against the second wave. To do.
- the first snubber capacitor capacity optimal for the first wave countermeasure and the second snubber capacitor capacity optimal for the second wave countermeasure are set.
- the first snubber capacitor is connected to the terminal portion of the power module, and the second snubber is connected between the terminal portions on the inverter circuit side of the fuse. Since the capacitor is connected, the influence of the short-circuit surge voltage can be suppressed even when the SiC-SW element is used as the SW element of the inverter circuit. As a result, an increase in the rating of the SiC-SW device can be avoided, and measures such as slowing down the switching speed and measures such as the addition of a protective circuit are no longer necessary, and the reduction in efficiency due to increased power converter costs and loss is suppressed. In addition, problems such as a decrease in reliability due to an increase in the number of parts can be avoided.
- the power module In the case of using a low-inductance bus bar (for example, a laminated bus bar) in which an insulator is interposed between the terminal portion of the power module and the terminal portion of the fuse as in the present embodiment, the power module The inductance component between the terminal portion and the terminal portion of the electrolytic capacitor is dominated by the fuse. For this reason, the connection position of the second snubber capacitor may not be the terminal part of the fuse, but may be a position close to the inverter circuit side from the terminal part of the fuse.
- Lpn2 is the sum of the wiring inductance component of the PN copper bus bar (22a, 22b) and the inductance component of the fuse 13, and between Lpn1, which is the wiring inductance component of the PN copper bus bar (23a, 23b), This is because the relationship of Lpn2> Lpn1 is always established, and the effect of suppressing the second surge voltage by the second snubber capacitor is obtained.
- the connection position of the second snubber capacitor is different from the connection position of the first snubber capacitor so that the roles of the first snubber capacitor and the second snubber capacitor are not affected (that is, Lpn1> 0). Need to be connected).
- Embodiment 2 FIG. In the first embodiment, the basic configuration of the power converter has been described. In the second embodiment, a configuration for reducing noise that increases when switching control of the SiC-SW element at high speed will be described.
- FIG. 5 is a diagram illustrating an equivalent circuit of a main part of the power converter according to the second embodiment.
- the inductance component (Lpn2) of the fuse 13 and the PN copper bus bar (22a, 22b) and the capacitance component C2 of the second snubber capacitor 19 are configured as an LC filter circuit 25.
- an LC filter circuit 25 it is possible to reduce noise that increases when the SiC-SW element is switching-controlled at high speed.
- Lpn1 Inductance component of PN copper bus bar (23a, 23b)
- Lpn2 Inductance component of fuse 13 and PN copper bus bar (22a, 22b)
- C1 Capacitance component of first snubber capacitor 18
- C2 Capacitance of second snubber capacitor 19 component
- Embodiment 3 FIG.
- the configuration of the power converter that effectively works in the phenomenon at the time of short-circuit interruption has been described.
- the configuration of the power converter that works effectively in a normal switching operation is explained. To do.
- FIG. 6 is a diagram illustrating an equivalent circuit of a main part of the power converter according to the third embodiment.
- the SiC-SBD 16 has an advantage that there is no recovery operation. However, since the internal parasitic resistance is small, there is a possibility that the SiC-MOSFET 15 may vibrate due to the ON of the SiC-MOSFET 15 connected in parallel to cause a malfunction to the peripheral device. Concerned. Therefore, in the third embodiment, as shown in FIG. 6, an RC snubber circuit 26 in which a capacitor 31 and a resistor 32 are connected in series is added. The vibration at the time of the ON operation of the SiC-MOSFET 15 is caused by the impedance inside the power module, and thus becomes a high-frequency vibration. Therefore, it is preferable to select the capacitor 31 of the RC snubber circuit 26 having a low capacitance and a small parasitic inductance value.
- the impedance of the RC snubber circuit 26 is expressed by the following equation (2). Therefore, the RC snubber circuit constant is close to the vibration frequency ⁇ n expressed by the following equation (3), and the resistance value is selected so that the damping factor ⁇ expressed by the equation (4) satisfies ⁇ ⁇ 0.8. It is preferable to do. In this case, it goes without saying that it is preferable to reduce the value of the parasitic inductance L.
- the RC snubber circuit 26 is shown to be provided at the terminal portion of the power module or outside, but may be provided inside the power module.
- FIG. FIG. 7 is a diagram illustrating the configuration of the power converter according to the fourth embodiment, which is different from the first embodiment in that the second snubber capacitor 19 is configured as an RDC snubber circuit 28. About others, it is the same as that of Embodiment 1, and while attaching
- the resistor 34 and the second snubber capacitor 19 provided in the RDC snubber circuit 28 operate as a snubber circuit, and the diode 35 performs a clamping operation. Therefore, according to the power converter which concerns on Embodiment 4, it becomes possible to heighten a surge suppression effect rather than Embodiment 1 by snubber operation
- the second snubber capacitor 19 is configured as an RDC snubber circuit.
- the first snubber capacitor 18 may be configured as an RDC snubber circuit. That is, at least one of the first snubber capacitor 18 and the second snubber capacitor 19 may be configured as an RDC snubber circuit.
- the surge suppression effect can be further enhanced. An effect is obtained.
- the second snubber capacitor is configured as an RDC snubber circuit as shown in FIG. 7, but the first snubber capacitor may be configured as an RDC snubber circuit. That is, in the power converter according to the fourth embodiment, it is sufficient that at least one of the first and second snubber capacitors is configured as an RDC snubber circuit, and the surge suppression effect can be enhanced.
- the configurations shown in the above first to fourth embodiments are examples of the configuration of the present invention, and can be combined with other known techniques, and can be combined within the scope of the present invention. Needless to say, the configuration may be modified by omitting the unit.
- the present invention is useful as a power converter that can protect the power module by suppressing the influence of the short-circuit surge voltage.
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Abstract
A power converter in which a fuses (13a, 13b) are respectively provided to DC lines (10a, 10b) between an electrolytic capacitor (11) and power modules (14) (14a-14c) constituting an inverter circuit (12), wherein first snubber capacitors (18) (18a-18c) are connected to terminal parts of the power modules (14), and a second snubber capacitor (19) is connected between the terminal part (9a) on the inverter circuit (12) side of the fuses (13a, 13b), and a terminal part (9b).
Description
本発明は、電力変換器に関する。
The present invention relates to a power converter.
ヒューズを具備する電力変換器として、例えば下記特許文献1に知られたものがある。この特許文献1では、所定結線されたスイッチング素子群に近接して並列接続され、スイッチングによる高周波の電流リップルを吸収する高耐圧のフィルムコンデンサと、スイッチング素子群にヒューズを介して並列接続され、基本周波数に起因する脈動を抑制する電解コンデンサ群とを具備する構成を開示している。
As a power converter having a fuse, for example, there is one known in Patent Document 1 below. In Patent Document 1, a high-voltage film capacitor that is connected in parallel to a switching element group that is connected in a predetermined manner and absorbs a high-frequency current ripple due to switching, and a switching element group that is connected in parallel via a fuse. The structure which comprises the electrolytic capacitor group which suppresses the pulsation resulting from a frequency is disclosed.
最近の技術動向として、高耐圧および低損失であり、かつ、高電流、高温度および高周波での動作が可能である炭化珪素(SiC:Silicon Carbide)をベース材とするスイッチング素子(以下「SiC-SW素子」と表記)が注目されている。
As a recent technical trend, a switching element based on silicon carbide (SiC), which has a high withstand voltage and low loss, and can operate at high current, high temperature and high frequency (hereinafter referred to as “SiC-”). Attention has been paid to “SW element”.
一方、このSiC-SW素子を用いて電力変換器を構成する場合、SiC-SW素子は、スイッチング速度が速いため、SiC-SW素子が短絡故障を起こした場合には、配線インダクタンスにより発生するサージ電圧(短絡サージ電圧)が非常に大きくなる。
On the other hand, when a power converter is configured using this SiC-SW element, since the SiC-SW element has a high switching speed, when the SiC-SW element causes a short-circuit fault, a surge generated by wiring inductance is generated. The voltage (short circuit surge voltage) becomes very large.
さらに、ヒューズを具備する電力変換器の場合、ヒューズの部分で正側(P)ブスバと負側(N)ブスバとを対とするPNブスバの対向が崩れるのと共に、ヒューズ自身のインダクタンスも加わり、短絡サージ電圧が非常に大きくなり、この短絡サージ電圧がSiC-SW素子を搭載するSiCパワーモジュール(以下単に「パワーモジュール」という)の最大定格を超える可能性がある。このため、ヒューズを具備する電力変換器にSiC-SW素子を適用する場合、短絡サージ電圧に対する何らかの対策が必要となる。なお、上記特許文献1には、短絡サージ電圧に対する考慮は為されていない。
Furthermore, in the case of a power converter equipped with a fuse, the opposite of the PN bus bar with the positive side (P) bus bar and the negative side (N) bus bar in the fuse portion collapses, and the inductance of the fuse itself is also added, The short-circuit surge voltage becomes very large, and this short-circuit surge voltage may exceed the maximum rating of the SiC power module (hereinafter simply referred to as “power module”) on which the SiC-SW element is mounted. For this reason, when a SiC-SW element is applied to a power converter having a fuse, some countermeasure against a short-circuit surge voltage is required. In Patent Document 1, no consideration is given to the short-circuit surge voltage.
本発明は、上記に鑑みてなされたものであって、ヒューズを具備する電力変換器にSiC-SW素子を適用する場合であっても、短絡サージ電圧の影響を抑制してパワーモジュールを保護することができる電力変換器を提供することを目的とする。
The present invention has been made in view of the above, and protects a power module by suppressing the influence of a short-circuit surge voltage even when a SiC-SW element is applied to a power converter having a fuse. An object of the present invention is to provide a power converter that can be used.
上述した課題を解決し、目的を達成するために、本発明は、平滑コンデンサとインバータ回路を構成するSiCパワーモジュールとの間の高電位側直流ラインおよび低電位側直流ラインのそれぞれに過電流保護素子を設けた電力変換器において、前記SiCパワーモジュールの端子部に接続される第1のスナバコンデンサと、前記過電流保護素子と前記インバータ回路との間における前記高電位側直流ラインと前記低電位側直流ラインとの間に接続される第2のスナバコンデンサと、を備え、前記第2のスナバコンデンサは、その接続位置から前記第1のスナバコンデンサの接続位置までの間の配線インダクタンス成分よりも、その接続位置から前記過電流保護素子までの配線インダクタンス成分と当該過電流保護素子のインダクタンス成分との和の方が大きくなるように接続されていることを特徴とする。
In order to solve the above-described problems and achieve the object, the present invention provides overcurrent protection for each of the high potential side DC line and the low potential side DC line between the smoothing capacitor and the SiC power module constituting the inverter circuit. In a power converter provided with an element, a first snubber capacitor connected to a terminal portion of the SiC power module, the high potential side DC line and the low potential between the overcurrent protection element and the inverter circuit A second snubber capacitor connected to the side DC line, wherein the second snubber capacitor is more than a wiring inductance component between the connection position and the connection position of the first snubber capacitor. The wiring inductance component from the connection position to the overcurrent protection element and the inductance component of the overcurrent protection element. Wherein the direction of the sum is connected so as to increase the.
この発明によれば、ヒューズを具備する電力変換器にSiC-SW素子を適用する場合であっても、短絡サージ電圧の影響を抑制してパワーモジュールを保護することができる、という効果を奏する。
According to the present invention, even when a SiC-SW element is applied to a power converter having a fuse, there is an effect that the power module can be protected by suppressing the influence of the short-circuit surge voltage.
以下に添付図面を参照し、本発明の実施の形態に係る電力変換器について説明する。なお、以下に示す実施の形態により本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 with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.
実施の形態1.
図1は、実施の形態1に係る電力変換器の構成を示す回路図である。実施の形態1に係る電力変換器は、図1に示すように、高電位(P電位)側のDCライン10aと低電位(N電位)側のDCライン10bとの間に接続される平滑コンデンサとしての電解コンデンサ11と、パワーモジュール14(14a,14b,14c)を有し直流電力を交流電力に変換するインバータ回路12と、電解コンデンサ11とインバータ回路12との間に介在するように、DCライン10a,10b間に挿入される過電流保護素子としてのヒューズ13(13a,13b)と、パワーモジュール14(14a,14b,14c)における各端子部8a,8bに並列に接続される第1のスナバコンデンサ18(18a,18b,18c)と、ヒューズ13a,13bが備える端子のうち、インバータ回路12における高電位側の直流部との電気的接続に使用する端子部9a(高電位側の直流(DC)ライン10aに挿入されるヒューズ13aの端子部)と、インバータ回路12における低電位側の直流部との電気的接続に使用する端子部9b(低電位側のDCライン10bに挿入されるヒューズ13bの端子部)との間に接続される第2のスナバコンデンサ19と、を備えて構成される。Embodiment 1 FIG.
1 is a circuit diagram showing a configuration of a power converter according toEmbodiment 1. FIG. As shown in FIG. 1, the power converter according to the first embodiment includes a smoothing capacitor connected between a high potential (P potential) side DC line 10a and a low potential (N potential) side DC line 10b. As an electrolytic capacitor 11, an inverter circuit 12 having a power module 14 (14 a, 14 b, 14 c) and converting DC power into AC power, and a DC DC so as to be interposed between the electrolytic capacitor 11 and the inverter circuit 12. A fuse 13 (13a, 13b) as an overcurrent protection element inserted between the lines 10a, 10b and a first connected in parallel to each terminal portion 8a, 8b in the power module 14 (14a, 14b, 14c) Of the terminals provided in the snubber capacitor 18 (18a, 18b, 18c) and the fuses 13a, 13b, the high potential side in the inverter circuit 12 Electrical connection between the terminal portion 9a (terminal portion of the fuse 13a inserted in the high potential side direct current (DC) line 10a) and the low potential side direct current portion in the inverter circuit 12 used for electrical connection with the direct current portion And a second snubber capacitor 19 connected between the terminal portion 9b used for connection (the terminal portion of the fuse 13b inserted in the DC line 10b on the low potential side).
図1は、実施の形態1に係る電力変換器の構成を示す回路図である。実施の形態1に係る電力変換器は、図1に示すように、高電位(P電位)側のDCライン10aと低電位(N電位)側のDCライン10bとの間に接続される平滑コンデンサとしての電解コンデンサ11と、パワーモジュール14(14a,14b,14c)を有し直流電力を交流電力に変換するインバータ回路12と、電解コンデンサ11とインバータ回路12との間に介在するように、DCライン10a,10b間に挿入される過電流保護素子としてのヒューズ13(13a,13b)と、パワーモジュール14(14a,14b,14c)における各端子部8a,8bに並列に接続される第1のスナバコンデンサ18(18a,18b,18c)と、ヒューズ13a,13bが備える端子のうち、インバータ回路12における高電位側の直流部との電気的接続に使用する端子部9a(高電位側の直流(DC)ライン10aに挿入されるヒューズ13aの端子部)と、インバータ回路12における低電位側の直流部との電気的接続に使用する端子部9b(低電位側のDCライン10bに挿入されるヒューズ13bの端子部)との間に接続される第2のスナバコンデンサ19と、を備えて構成される。
1 is a circuit diagram showing a configuration of a power converter according to
インバータ回路12に設けられるパワーモジュール14(14a,14b,14c)は、並列に接続されて三相インバータ回路を構成する。パワーモジュール14aは、例えば、SiC-MOSFET15と、SiC-MOSFET15に逆並列に接続されるSiCショットキーバリアダイオード(SiC Schottky-Barrier Diode:SiC-SBD)16からなる回路1組をSW素子(すなわち、SiC-SW素子)とし、このSiC-SW素子の2組を直列に接続した回路を構成する。ここで、SiC-SW素子2組を直列に接続した回路を「アーム」と呼ぶ。他のパワーモジュール14b,14cについても同様に構成される。すなわち、図示のインバータ回路12は、3つのアームが並列に接続された三相インバータ回路であり、各パワーモジュールにおけるSiC-SW素子同士の直列接続点から引き出されたケーブル60に接続されるモータ50は、三相モータ(例えば、同期電動機、誘導電動機など)である。なお、図1では、三相インバータ回路を例示しているが、必要な相数に応じた数のアームを設ければよい。また、図1では、直列接続される2組のSW素子をモジュール内に収容する構成を例示しているが、6組のSiC-SW素子を1つのモジュール内に収容してインバータ回路12を構成してもよいし、1組のSiC-SW素子が1つのモジュール内に収容された6個のモジュールにてインバータ回路12を構成してもよい。
The power modules 14 (14a, 14b, 14c) provided in the inverter circuit 12 are connected in parallel to form a three-phase inverter circuit. The power module 14a includes, for example, an SW element (that is, a SiC Schottky-Barrier Diode (SiC-SBD) 16) connected to the SiC-MOSFET 15 and the SiC-MOSFET 15 in antiparallel. SiC-SW element), and a circuit in which two sets of the SiC-SW elements are connected in series is configured. Here, a circuit in which two sets of SiC-SW elements are connected in series is referred to as an “arm”. The other power modules 14b and 14c are similarly configured. That is, the illustrated inverter circuit 12 is a three-phase inverter circuit in which three arms are connected in parallel, and a motor 50 connected to a cable 60 drawn from a series connection point of SiC-SW elements in each power module. Is a three-phase motor (for example, a synchronous motor, an induction motor, etc.). Although FIG. 1 illustrates a three-phase inverter circuit, a number of arms corresponding to the required number of phases may be provided. Further, FIG. 1 illustrates a configuration in which two sets of SW elements connected in series are accommodated in a module, but an inverter circuit 12 is configured by accommodating six sets of SiC-SW elements in one module. Alternatively, the inverter circuit 12 may be configured by six modules in which one set of SiC-SW elements is accommodated in one module.
図2は、実施の形態1に係る電力変換器の構造的な配置例を示す図であり、電力変換器の内部を上方から見た上面図である。図2では、図1に示した電解コンデンサ11自体は図示せず、正負一対の電解コンデンサ接続端子21を示している。電解コンデンサ11は、上面に見えるP電位銅ブスバ22aに電気的に接続される電解コンデンサP端子24aと、裏面側にあるN電位銅ブスバ22bに電気的に接続される電解コンデンサN端子24bとの間に接続される。
FIG. 2 is a diagram illustrating a structural arrangement example of the power converter according to the first embodiment, and is a top view of the inside of the power converter as viewed from above. 2, the electrolytic capacitor 11 itself shown in FIG. 1 is not shown, and a pair of positive and negative electrolytic capacitor connection terminals 21 is shown. The electrolytic capacitor 11 includes an electrolytic capacitor P terminal 24a electrically connected to the P potential copper bus bar 22a visible on the upper surface, and an electrolytic capacitor N terminal 24b electrically connected to the N potential copper bus bar 22b on the back surface side. Connected between.
パワーモジュール14(14a,14b,14c)は、上面に見えるP電位銅ブスバ23aに電気的に接続されるP端子25aと、裏面側にあるN電位銅ブスバ23bに電気的に接続されるN端子25bとの間に接続される。出力端子29は、SiC-SW素子同士の直列接続点に設けられる端子である。この出力端子29は、ケーブル60(図1参照)に電気的に接続される。
The power module 14 (14a, 14b, 14c) includes a P terminal 25a electrically connected to the P potential copper bus bar 23a visible on the upper surface and an N terminal electrically connected to the N potential copper bus bar 23b on the back surface side. 25b. The output terminal 29 is a terminal provided at a series connection point between SiC-SW elements. The output terminal 29 is electrically connected to the cable 60 (see FIG. 1).
なお、破線のハッチングで示した領域は、P電位銅ブスバ22a,23aにおけるくり抜きの部分を示すものである。
In addition, the area | region shown with the hatching of the broken line shows the hollow part in P electric potential copper bus bar 22a, 23a.
P電位銅ブスバ22a,23aおよびN電位銅ブスバ22b,23bは、それぞれの銅ブスバ間に絶縁物を挟んで近接対向配置され、それぞれの銅ブスバによるPNラインのインダクタンス成分を極力小さくして、SiC-SW素子が短絡したときのサージ電圧(以下「短絡サージ電圧」と称する)が小さくなるように構成されている。
The P potential copper bus bars 22a and 23a and the N potential copper bus bars 22b and 23b are arranged in close proximity to each other with an insulator interposed between the copper bus bars, and the inductance component of the PN line by each copper bus bar is made as small as possible. The surge voltage when the SW element is short-circuited (hereinafter referred to as “short-circuit surge voltage”) is reduced.
ヒューズ13(13a,13b)は、電力変換器の容量が大きい場合に設けられる。電力変換器の容量が大きい場合、電解コンデンサ11にも大きなエネルギーが蓄積されるので、パワーモジュール14の短絡事故が起きた場合に電解コンデンサ11の大きなエネルギーによる事故拡大を回避するために、ヒューズ13が必要となる。なお、ヒューズ13(13a,13b)を設けない電力変換器の場合、P電位銅ブスバ22aとP電位銅ブスバ23bおよびN電位銅ブスバ22bとN電位銅ブスバ23bは、それぞれが一体化されて構成されるのが通常である。
The fuse 13 (13a, 13b) is provided when the capacity of the power converter is large. When the capacity of the power converter is large, a large amount of energy is also stored in the electrolytic capacitor 11. Therefore, in order to avoid the accidental expansion due to the large energy of the electrolytic capacitor 11 when a short circuit accident of the power module 14 occurs, the fuse 13 Is required. In the case of a power converter not provided with fuse 13 (13a, 13b), P potential copper bus bar 22a, P potential copper bus bar 23b, N potential copper bus bar 22b, and N potential copper bus bar 23b are integrated with each other. It is usually done.
パワーモジュール14(14a,14b,14c)の図示しないP電位端子、N電位端子間には、第1のスナバコンデンサ18(18a,18b,18c)が接続される。なお、図2では、パワーモジュール14毎に第1のスナバコンデンサ18を2並列とする配置例を示し、また、電力変換器の信頼性向上のため、P電位およびN電位毎にヒューズ13を5並列とする配置例(注:N電位側は不図示)を示しているが、何れも一例であり、この配置例に限定されるものではない。
A first snubber capacitor 18 (18a, 18b, 18c) is connected between a P potential terminal and an N potential terminal (not shown) of the power module 14 (14a, 14b, 14c). 2 shows an arrangement example in which two first snubber capacitors 18 are arranged in parallel for each power module 14, and 5 fuses 13 are provided for each P potential and N potential in order to improve the reliability of the power converter. Although an arrangement example in parallel (note: N potential side is not shown) is shown, all are examples and are not limited to this arrangement example.
上記のような構成において、背景技術の項でも説明したが、SiC-MOSFET15はスイッチング速度が速く、短絡故障時には配線インダクタンスに起因して発生するサージ電圧が非常に大きくなる。これに加え、SiC-MOSFET15を使用し、且つ、上記の理由でヒューズ13を使用すると、ヒューズ13の部分でPN銅ブスバの対向が崩れるのと共に、ヒューズ13自身のインダクタンス成分も加わり、電解コンデンサ11とパワーモジュール14との間のインダクタンス成分が増加する。このため、これら2つの要因に起因して、パワーモジュール14に発生するサージ電圧が大きくなり、最大定格を超える可能性があり、何らかの対策が必要となる。
In the configuration as described above, as described in the background section, the SiC-MOSFET 15 has a high switching speed, and a surge voltage generated due to the wiring inductance at the time of a short circuit failure becomes very large. In addition to this, when the SiC-MOSFET 15 is used and the fuse 13 is used for the above-described reason, the opposing portion of the PN copper bus bar is broken at the fuse 13 portion, and the inductance component of the fuse 13 itself is also added. And the inductance component between the power module 14 increases. For this reason, due to these two factors, the surge voltage generated in the power module 14 becomes large and may exceed the maximum rating, and some countermeasure is required.
図3は、実施の形態1の電力変換器における要部の等価回路を示す図である。図3において、Lsはパワーモジュール内部の配線インダクタンス成分であり、Lpn1はPN銅ブスバ(23a,23b)による配線インダクタンス成分であり、Lpn2はPN銅ブスバ(22a,22b)による配線インダクタンス成分と、ヒューズ13のインダクタンス成分との和である。第1および第2のスナバコンデンサ(18,19)については、本来のキャパシタンス成分に加え、寄生インダクタンス成分および寄生抵抗成分を付加して示している。SiC-SW素子については、SiC-MOSFET15はスイッチ記号、SiC-SBD16は、キャパシタンス成分と抵抗成分とで示している。なお、その他の要素は図1または図2と同一符号を用いて示している。
FIG. 3 is a diagram showing an equivalent circuit of a main part of the power converter according to the first embodiment. In FIG. 3, Ls is a wiring inductance component inside the power module, Lpn1 is a wiring inductance component due to the PN copper bus bar (23a, 23b), Lpn2 is a wiring inductance component due to the PN copper bus bar (22a, 22b), and a fuse 13 and the inductance component. The first and second snubber capacitors (18, 19) are shown with a parasitic inductance component and a parasitic resistance component added to the original capacitance component. Regarding the SiC-SW element, the SiC-MOSFET 15 is indicated by a switch symbol, and the SiC-SBD 16 is indicated by a capacitance component and a resistance component. Other elements are denoted by the same reference numerals as those in FIG. 1 or FIG.
図4は、SiC-MOSFET15に発生するサージ電圧波形の一例である。なお、図4は、実施の形態1の構成において、第2のスナバコンデンサ19を設けない場合の波形である。図4において、横軸は時間、縦軸は電圧であり、波形K1はSiC-MOSFET15に発生するゲート-ソース間電圧(Vgs)であり、波形K2はSiC-MOSFET15に発生するドレイン-ソース間電圧(Vds)である。
FIG. 4 is an example of a surge voltage waveform generated in the SiC-MOSFET 15. FIG. 4 shows a waveform when the second snubber capacitor 19 is not provided in the configuration of the first embodiment. In FIG. 4, the horizontal axis represents time, the vertical axis represents voltage, the waveform K1 represents the gate-source voltage (Vgs) generated in the SiC-MOSFET 15, and the waveform K2 represents the drain-source voltage generated in the SiC-MOSFET 15. (Vds).
図示のように、SiC-SW素子に発生するサージ電圧は、第1波(縦軸方向に立ち上がる成分)と第1波の後に来る第2波(楕円で囲んだ部分)とがある。第1波は、主にLsと第1のスナバコンデンサ18との関係により発生し、第2波は、主にLpn(Lpn1とLpn2の和)と第1のスナバコンデンサ18との関係により発生する。よって、第1波の対策としては、第1のスナバコンデンサ18の寄生インダクタンスと抵抗が小さいほうがよい。なお、一般的にコンデンサ容量が小さいほうが寄生インダクタンス成分および寄生抵抗成分が小さいため、同様の容量であれば並列接続の方がよい。
As shown in the figure, the surge voltage generated in the SiC-SW element has a first wave (a component rising in the vertical axis direction) and a second wave (portion surrounded by an ellipse) that comes after the first wave. The first wave is generated mainly by the relationship between Ls and the first snubber capacitor 18, and the second wave is generated mainly by the relationship between Lpn (the sum of Lpn1 and Lpn2) and the first snubber capacitor 18. . Therefore, as a countermeasure against the first wave, it is preferable that the parasitic inductance and resistance of the first snubber capacitor 18 are small. In general, the smaller the capacitance of the capacitor, the smaller the parasitic inductance component and the parasitic resistance component.
一方、第2波の対策としては、第1のスナバコンデンサ18の容量が大きくなくてはならない。第2波に起因するインダクタンス成分にはLsだけでなくLpnが加わるからである。なお、もしLpnを小さくすることができれば、第2波を意識した特別な対策は不要である。しかしながら、Lpnを小さくすること困難である。理由は以下の2点である。第1の理由は、実施の形態1が想定する電力変換器は、ヒューズ13を必要とする電力変換器であり、ヒューズ自体のインダクタンス成分を小さくすることが困難であるという点にある。第2の理由は、PNブスバとしてインダクタンス成分の非常に小さなラミネートブスバを用いたとしても、ヒューズ13のところでラミネートブスバが分断されると共に、ヒューズ13によってラミネートブスバの対向性が崩れるため、インダクタンス成分の極小化には限界があるからである。
On the other hand, as a countermeasure against the second wave, the capacity of the first snubber capacitor 18 must be large. This is because not only Ls but also Lpn is added to the inductance component caused by the second wave. In addition, if Lpn can be reduced, a special measure in consideration of the second wave is unnecessary. However, it is difficult to reduce Lpn. The reason is the following two points. The first reason is that the power converter assumed in the first embodiment is a power converter that requires the fuse 13, and it is difficult to reduce the inductance component of the fuse itself. The second reason is that even if a laminated bus bar having a very small inductance component is used as the PN bus bar, the laminated bus bar is divided at the fuse 13 and the opposing property of the laminated bus bar is broken by the fuse 13. This is because there is a limit to minimizing the inductance component.
よって、第1波と第2波の双方の対策を満足させるにはLpnを小さくする以外の対策が必要となる。図1を参照すると、パワーモジュール14に接続する第1のスナバコンデンサ18の容量を増やすことが考えられる。しかしながら、図2において、パワーモジュール14周りの構成を見れば明らかなように、第1のスナバコンデンサ18の容量を増やすためのスペースは殆どないのが実情である。第1のスナバコンデンサ18の容量不足は、SiC-MOSFET15の定格を大きくし、スイッチングスピードを遅くし、また、保護回路の追加を余儀なくされるため、電力変換器のコスト増、損失増加による効率の低下、部品点数増加による信頼性の低下などの問題が生ずる。
Therefore, measures other than reducing Lpn are required to satisfy both the first and second wave measures. Referring to FIG. 1, it is conceivable to increase the capacity of the first snubber capacitor 18 connected to the power module 14. However, as is apparent from the configuration around the power module 14 in FIG. 2, the actual situation is that there is almost no space for increasing the capacity of the first snubber capacitor 18. The shortage of the capacity of the first snubber capacitor 18 increases the rating of the SiC-MOSFET 15, slows the switching speed, and necessitates the addition of a protection circuit. Problems such as a decrease in reliability due to a decrease in the number of parts occur.
そこで、実施の形態1の電力変換器では、図1および図2に示すように、ヒューズ13に具備される端子9a,9bに第2のスナバコンデンサ19を接続する対策を行う。
Therefore, in the power converter of the first embodiment, as shown in FIGS. 1 and 2, measures are taken to connect the second snubber capacitor 19 to the terminals 9 a and 9 b provided in the fuse 13.
なお、図2では、第2のスナバコンデンサ19として、上面側(P電位側)に設けられた5個のヒューズ13aの空きスペースを利用して6個のコンデンサを配置する例を開示しているが、6個に限定されるものでないことは言うまでもない。
Note that FIG. 2 discloses an example in which six capacitors are arranged as the second snubber capacitor 19 using the empty space of the five fuses 13a provided on the upper surface side (P potential side). However, it goes without saying that the number is not limited to six.
第2のスナバコンデンサ19の配置に関する肝要な点は、第2のスナバコンデンサ19を接続するヒューズ13の端子9a,9bは、電解コンデンサ11側の端子(すなわち、電解コンデンサ11との電気的接続をとる端子)ではなく、インバータ回路12側の端子9a,9b(すなわち、インバータ回路12との電気的接続をとる端子)であるという点である。このような接続により、電解コンデンサ11に蓄積された大きなエネルギーがヒューズ13のインダクタンス成分を介してパワーモジュール14に伝達されるのを、第2のスナバコンデンサ19にて効果的に減衰させることが可能となる。
The important point regarding the arrangement of the second snubber capacitor 19 is that the terminals 9a and 9b of the fuse 13 to which the second snubber capacitor 19 is connected are terminals on the electrolytic capacitor 11 side (that is, electrical connection with the electrolytic capacitor 11). Terminal 9a, 9b on the inverter circuit 12 side (that is, a terminal for electrical connection with the inverter circuit 12). With such a connection, the second snubber capacitor 19 can effectively attenuate the large energy accumulated in the electrolytic capacitor 11 being transmitted to the power module 14 via the inductance component of the fuse 13. It becomes.
第1のスナバコンデンサ18の容量値は、第2のスナバコンデンサ19の容量値よりも小さいことが好ましい。第1のスナバコンデンサ18として容量値の小さなものを選定すれば、必然的に寄生インダクタンス成分と寄生抵抗成分とが小さいものを選定したことになる。これにより、第1波対策に最適な第1のスナバコンデンサ容量が設定されたことになる。
The capacitance value of the first snubber capacitor 18 is preferably smaller than the capacitance value of the second snubber capacitor 19. If a capacitor having a small capacitance value is selected as the first snubber capacitor 18, a capacitor having a small parasitic inductance component and parasitic resistance component is necessarily selected. As a result, the first snubber capacitor capacity optimum for the first wave countermeasure is set.
なお、第1のスナバコンデンサ18の容量値を小さくすると第2波対策にはマイナスに作用するが、第2のスナバコンデンサ19が存在するので問題ない。また、第2のスナバコンデンサ19の容量値を大きくすれば、第2波対策に有効に作用する。さらに、第1のスナバコンデンサ容量と、追加した第2のスナバコンデンサ容量とは並列接続の関係にあるため、第1および第2のスナバコンデンサ容量の合計値は第2波対策として効果的に作用する。
Note that, if the capacitance value of the first snubber capacitor 18 is reduced, the second wave countermeasure is negatively affected, but there is no problem because the second snubber capacitor 19 exists. In addition, if the capacitance value of the second snubber capacitor 19 is increased, the second snubber capacitor 19 effectively acts against the second wave. Furthermore, since the first snubber capacitor capacity and the added second snubber capacitor capacity are in a parallel connection relationship, the total value of the first and second snubber capacitor capacities effectively acts as a countermeasure against the second wave. To do.
以上の構成により、第1波対策に最適な第1のスナバコンデンサ容量と第2波対策に最適な第2のスナバコンデンサ容量とが設定されたことになる。
With the above configuration, the first snubber capacitor capacity optimal for the first wave countermeasure and the second snubber capacitor capacity optimal for the second wave countermeasure are set.
以上説明したように、実施の形態1に係る電力変換器によれば、パワーモジュールの端子部に第1のスナバコンデンサを接続し、ヒューズにおけるインバータ回路側の各端子部の間に第2のスナバコンデンサを接続したので、インバータ回路のSW素子としてSiC-SW素子を適用する場合であっても、短絡サージ電圧の影響を抑制することが可能となる。その結果、SiC-SW素子の定格増を回避でき、スイッチングスピードを遅くする対策や、保護回路追加等の対策なども不要となり、電力変換器のコスト増、損失増加による効率の低下を抑制することができ、また、部品点数増加による信頼性の低下などの問題を回避することが可能となる。
As described above, according to the power converter of the first embodiment, the first snubber capacitor is connected to the terminal portion of the power module, and the second snubber is connected between the terminal portions on the inverter circuit side of the fuse. Since the capacitor is connected, the influence of the short-circuit surge voltage can be suppressed even when the SiC-SW element is used as the SW element of the inverter circuit. As a result, an increase in the rating of the SiC-SW device can be avoided, and measures such as slowing down the switching speed and measures such as the addition of a protective circuit are no longer necessary, and the reduction in efficiency due to increased power converter costs and loss is suppressed. In addition, problems such as a decrease in reliability due to an increase in the number of parts can be avoided.
なお、本実施の形態のように、パワーモジュールの端子部とヒューズの端子部との間を、絶縁物を挟んで対向させた低インダクタンスのブスバ(例えばラミネートブスバ)を用いる場合、パワーモジュールの端子部から電解コンデンサの端子部までの間のインダクタンス成分はヒューズによるものが支配的となる。このため、第2のスナバコンデンサの接続位置はヒューズの端子部でなくてもよく、ヒューズの端子部からインバータ回路側に寄った位置でもよい。なぜなら、Lpn2は、PN銅ブスバ(22a,22b)の配線インダクタンス成分と、ヒューズ13のインダクタンス成分との和であり、PN銅ブスバ(23a,23b)の配線インダクタンス成分であるLpn1との間で、Lpn2>Lpn1の関係が常に成立し、第2のスナバコンデンサによるサージ電圧第2波の抑制効果が得られるからである。ただし、第1のスナバコンデンサと第2のスナバコンデンサの役割が被らないように、第2のスナバコンデンサの接続位置が第1のスナバコンデンサ接続位置と異なるように(つまり、Lpn1>0となるように)接続する必要がある。
In the case of using a low-inductance bus bar (for example, a laminated bus bar) in which an insulator is interposed between the terminal portion of the power module and the terminal portion of the fuse as in the present embodiment, the power module The inductance component between the terminal portion and the terminal portion of the electrolytic capacitor is dominated by the fuse. For this reason, the connection position of the second snubber capacitor may not be the terminal part of the fuse, but may be a position close to the inverter circuit side from the terminal part of the fuse. This is because Lpn2 is the sum of the wiring inductance component of the PN copper bus bar (22a, 22b) and the inductance component of the fuse 13, and between Lpn1, which is the wiring inductance component of the PN copper bus bar (23a, 23b), This is because the relationship of Lpn2> Lpn1 is always established, and the effect of suppressing the second surge voltage by the second snubber capacitor is obtained. However, the connection position of the second snubber capacitor is different from the connection position of the first snubber capacitor so that the roles of the first snubber capacitor and the second snubber capacitor are not affected (that is, Lpn1> 0). Need to be connected).
実施の形態2.
実施の形態1では、電力変換器の基本的な構成を説明したが、実施の形態2では、SiC-SW素子を高速でスイッチング制御する際に増加するノイズを低減させる構成について説明する。 Embodiment 2. FIG.
In the first embodiment, the basic configuration of the power converter has been described. In the second embodiment, a configuration for reducing noise that increases when switching control of the SiC-SW element at high speed will be described.
実施の形態1では、電力変換器の基本的な構成を説明したが、実施の形態2では、SiC-SW素子を高速でスイッチング制御する際に増加するノイズを低減させる構成について説明する。 Embodiment 2. FIG.
In the first embodiment, the basic configuration of the power converter has been described. In the second embodiment, a configuration for reducing noise that increases when switching control of the SiC-SW element at high speed will be described.
図5は、実施の形態2の電力変換器における要部の等価回路を示す図である。実施の形態2では、図5に示すように、ヒューズ13およびPN銅ブスバ(22a,22b)のインダクタンス成分(Lpn2)と、第2のスナバコンデンサ19の容量成分C2とをLCフィルタ回路25として構成する。このようなLCフィルタ回路25を構成すれば、SiC-SW素子が高速でスイッチング制御される際に増加するノイズを低減させることが可能となる。
FIG. 5 is a diagram illustrating an equivalent circuit of a main part of the power converter according to the second embodiment. In the second embodiment, as shown in FIG. 5, the inductance component (Lpn2) of the fuse 13 and the PN copper bus bar (22a, 22b) and the capacitance component C2 of the second snubber capacitor 19 are configured as an LC filter circuit 25. To do. If such an LC filter circuit 25 is configured, it is possible to reduce noise that increases when the SiC-SW element is switching-controlled at high speed.
なお、LCフィルタとしては、電解コンデンサ11からパワーモジュール14側を見たインピーダンスを表す下記(1)式に従って、Lpn2およびC2の値を選定すればよい。
In addition, what is necessary is just to select the value of Lpn2 and C2 according to the following (1) formula showing the impedance which looked at the power module 14 side from the electrolytic capacitor 11 as LC filter.
[1/{jω*(C1+C2)}]*[1/{(jω)^2*Lpn1*C1*C2/(C1+C2)+1}]*{(jω)^2*Lpn1*C1+1}+(jω*Lpn2) ……(1)
Lpn1:PN銅ブスバ(23a,23b)のインダクタンス成分
Lpn2:ヒューズ13およびPN銅ブスバ(22a,22b)のインダクタンス成分
C1:第1のスナバコンデンサ18の容量成分
C2:第2のスナバコンデンサ19の容量成分 [1 / {jω * (C1 + C2)}] * [1 / {(jω) ^ 2 * Lpn1 * C1 * C2 / (C1 + C2) +1}] * {(jω) ^ 2 * Lpn1 * C1 + 1} + (jω * Lpn2) (1)
Lpn1: Inductance component of PN copper bus bar (23a, 23b) Lpn2: Inductance component offuse 13 and PN copper bus bar (22a, 22b) C1: Capacitance component of first snubber capacitor 18 C2: Capacitance of second snubber capacitor 19 component
Lpn1:PN銅ブスバ(23a,23b)のインダクタンス成分
Lpn2:ヒューズ13およびPN銅ブスバ(22a,22b)のインダクタンス成分
C1:第1のスナバコンデンサ18の容量成分
C2:第2のスナバコンデンサ19の容量成分 [1 / {jω * (C1 + C2)}] * [1 / {(jω) ^ 2 * Lpn1 * C1 * C2 / (C1 + C2) +1}] * {(jω) ^ 2 * Lpn1 * C1 + 1} + (jω * Lpn2) (1)
Lpn1: Inductance component of PN copper bus bar (23a, 23b) Lpn2: Inductance component of
実施の形態3.
実施の形態1,2では、短絡遮断時の現象に効果的に働く電力変換器の構成について説明したが、実施の形態3では、通常のスイッチング動作時に効果的に働く電力変換器の構成について説明する。 Embodiment 3 FIG.
In the first and second embodiments, the configuration of the power converter that effectively works in the phenomenon at the time of short-circuit interruption has been described. In the third embodiment, the configuration of the power converter that works effectively in a normal switching operation is explained. To do.
実施の形態1,2では、短絡遮断時の現象に効果的に働く電力変換器の構成について説明したが、実施の形態3では、通常のスイッチング動作時に効果的に働く電力変換器の構成について説明する。 Embodiment 3 FIG.
In the first and second embodiments, the configuration of the power converter that effectively works in the phenomenon at the time of short-circuit interruption has been described. In the third embodiment, the configuration of the power converter that works effectively in a normal switching operation is explained. To do.
図6は、実施の形態3の電力変換器における要部の等価回路を示す図である。SiC-SBD16にはリカバリ動作はないという利点はある一方で、内部の寄生抵抗が小さいために並列に接続されるSiC-MOSFET15のONにより振動して周辺機器に誤動作を与える可能性がある点が懸念される。そこで、実施の形態3では、図6に示すように、コンデンサ31と抵抗32とを直列に接続したRCスナバ回路26を付加する。SiC-MOSFET15のON動作時の振動は、パワーモジュール内部のインピーダンスに起因するため、高周波数の振動となる。よって、RCスナバ回路26のコンデンサ31は、低容量で寄生インダクタンス値が小さなものを選定することが好ましい。
FIG. 6 is a diagram illustrating an equivalent circuit of a main part of the power converter according to the third embodiment. The SiC-SBD 16 has an advantage that there is no recovery operation. However, since the internal parasitic resistance is small, there is a possibility that the SiC-MOSFET 15 may vibrate due to the ON of the SiC-MOSFET 15 connected in parallel to cause a malfunction to the peripheral device. Concerned. Therefore, in the third embodiment, as shown in FIG. 6, an RC snubber circuit 26 in which a capacitor 31 and a resistor 32 are connected in series is added. The vibration at the time of the ON operation of the SiC-MOSFET 15 is caused by the impedance inside the power module, and thus becomes a high-frequency vibration. Therefore, it is preferable to select the capacitor 31 of the RC snubber circuit 26 having a low capacitance and a small parasitic inductance value.
なお、RCスナバ回路26のインピーダンスは下記(2)式のように表される。よって、RCスナバ回路の定数は、下記(3)式で表される振動周波数ωnと近接し、(4)式で表される減衰率ζが、ζ≧0.8となるよう抵抗値を選定することが好ましい。なお、この際、寄生インダクタンスLの値を小さくすることが好ましい、ことは言うまでもない。
The impedance of the RC snubber circuit 26 is expressed by the following equation (2). Therefore, the RC snubber circuit constant is close to the vibration frequency ωn expressed by the following equation (3), and the resistance value is selected so that the damping factor ζ expressed by the equation (4) satisfies ζ ≧ 0.8. It is preferable to do. In this case, it goes without saying that it is preferable to reduce the value of the parasitic inductance L.
{(jω)^2*L*C+jω*R*C+1}/(jω*C) ……(2)
{(Jω) ^ 2 * L * C + jω * R * C + 1} / (jω * C) (2)
ωn=1/{2*π*√(L*C))≒振動周波数 ……(3)
Ωn = 1 / {2 * π * √ (L * C)) ≈vibration frequency (3)
ζ=R/2*√(C/L) ……(4)
Ζ = R / 2 * √ (C / L) (4)
なお、実施の形態3では、図6のように、RCスナバ回路26をパワーモジュールの端子部もしくは外部に設けるように示したが、パワーモジュール内部に設けるようにしてもよい。
In the third embodiment, as shown in FIG. 6, the RC snubber circuit 26 is shown to be provided at the terminal portion of the power module or outside, but may be provided inside the power module.
実施の形態4.
図7は、実施の形態4に係る電力変換器の構成を示す図であり、第2のスナバコンデンサ19をRDCスナバ回路28として構成している点が実施の形態1との相違点である。その他については、実施の形態1と同一であり、同一の構成部については同一の符号を付すと共に、重複する説明は省略する。 Embodiment 4 FIG.
FIG. 7 is a diagram illustrating the configuration of the power converter according to the fourth embodiment, which is different from the first embodiment in that thesecond snubber capacitor 19 is configured as an RDC snubber circuit 28. About others, it is the same as that of Embodiment 1, and while attaching | subjecting the same code | symbol about the same component, the overlapping description is abbreviate | omitted.
図7は、実施の形態4に係る電力変換器の構成を示す図であり、第2のスナバコンデンサ19をRDCスナバ回路28として構成している点が実施の形態1との相違点である。その他については、実施の形態1と同一であり、同一の構成部については同一の符号を付すと共に、重複する説明は省略する。 Embodiment 4 FIG.
FIG. 7 is a diagram illustrating the configuration of the power converter according to the fourth embodiment, which is different from the first embodiment in that the
図7において、RDCスナバ回路28に具備される抵抗34および第2のスナバコンデンサ19はスナバ回路として動作し、ダイオード35はクランプ動作を行う。よって、実施の形態4に係る電力変換器によれば、スナバ動作およびクランプ動作により、実施の形態1よりもサージ抑制効果を高めることが可能となる。
7, the resistor 34 and the second snubber capacitor 19 provided in the RDC snubber circuit 28 operate as a snubber circuit, and the diode 35 performs a clamping operation. Therefore, according to the power converter which concerns on Embodiment 4, it becomes possible to heighten a surge suppression effect rather than Embodiment 1 by snubber operation | movement and clamp operation | movement.
なお、実施の形態4では、第2のスナバコンデンサ19をRDCスナバ回路として構成する形態を説明したが、第1のスナバコンデンサ18をRDCスナバ回路として構成してもよい。すなわち、第1のスナバコンデンサ18および第2のスナバコンデンサ19のうちの少なくとも一つがRDCスナバ回路として構成されていてもよい。
In the fourth embodiment, the second snubber capacitor 19 is configured as an RDC snubber circuit. However, the first snubber capacitor 18 may be configured as an RDC snubber circuit. That is, at least one of the first snubber capacitor 18 and the second snubber capacitor 19 may be configured as an RDC snubber circuit.
以上説明したように、実施の形態4に係る電力変換器によれば、前記第1および第2のスナバコンデンサの少なくとも一つがRDCスナバ回路として構成したので、サージ抑制効果をさらに高めることができるという効果が得られる。
As described above, according to the power converter of the fourth embodiment, since at least one of the first and second snubber capacitors is configured as an RDC snubber circuit, the surge suppression effect can be further enhanced. An effect is obtained.
なお、実施の形態4では、図7のように、第2のスナバコンデンサをRDCスナバ回路として構成する例を示したが、第1のスナバコンデンサをRDCスナバ回路として構成してもよい。すなわち、実施の形態4の電力変換器では、第1および第2のスナバコンデンサの少なくとも一つがRDCスナバ回路として構成されていればよく、サージ抑制効果を高めることが可能となる。
In the fourth embodiment, the second snubber capacitor is configured as an RDC snubber circuit as shown in FIG. 7, but the first snubber capacitor may be configured as an RDC snubber circuit. That is, in the power converter according to the fourth embodiment, it is sufficient that at least one of the first and second snubber capacitors is configured as an RDC snubber circuit, and the surge suppression effect can be enhanced.
また、以上の実施の形態1~4に示した構成は、本発明の構成の一例であり、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、一部を省略する等、変更して構成することも可能であることは言うまでもない。
The configurations shown in the above first to fourth embodiments are examples of the configuration of the present invention, and can be combined with other known techniques, and can be combined within the scope of the present invention. Needless to say, the configuration may be modified by omitting the unit.
以上のように、本発明は、短絡サージ電圧の影響を抑制してパワーモジュールを保護することができる電力変換器として有用である。
As described above, the present invention is useful as a power converter that can protect the power module by suppressing the influence of the short-circuit surge voltage.
8a,8b 端子部(パワーモジュール)、9a,9b 端子部(ヒューズ)、10a DCライン(高電位側)、10b DCライン(低電位側)、11 電解コンデンサ、12 インバータ回路、13,13a,13b ヒューズ、14,14a,14b,14c パワーモジュール(SiCパワーモジュール)、18,18a,18b,18c 第1のスナバコンデンサ、19 第2のスナバコンデンサ、21 電解コンデンサ接続端子、22a,23a P電位銅ブスバ、22b,23b N電位銅ブスバ、24a 電解コンデンサP端子、24b 電解コンデンサN端子、25a P端子、25b N端子、26 RCスナバ回路、28 RDCスナバ回路、29 出力端子、31 コンデンサ、32,34 抵抗、35 ダイオード、50 モータ、60 ケーブル。
8a, 8b terminal part (power module), 9a, 9b terminal part (fuse), 10a DC line (high potential side), 10b DC line (low potential side), 11 electrolytic capacitor, 12 inverter circuit, 13, 13a, 13b Fuse, 14, 14a, 14b, 14c Power module (SiC power module), 18, 18a, 18b, 18c First snubber capacitor, 19 Second snubber capacitor, 21 Electrolytic capacitor connection terminal, 22a, 23a P potential copper bus bar 22b, 23b N potential copper bus bar, 24a electrolytic capacitor P terminal, 24b electrolytic capacitor N terminal, 25a P terminal, 25b N terminal, 26 RC snubber circuit, 28 RDC snubber circuit, 29 output terminal, 31 capacitor, 32, 34 resistance , 35 die Over de, 50 motor, 60 cable.
Claims (6)
- 平滑コンデンサとインバータ回路を構成するSiCパワーモジュールとの間の高電位側直流ラインおよび低電位側直流ラインのそれぞれに過電流保護素子を設けた電力変換器において、
前記SiCパワーモジュールの端子部に接続される第1のスナバコンデンサと、
前記過電流保護素子と前記インバータ回路との間における前記高電位側直流ラインと前記低電位側直流ラインとの間に接続される第2のスナバコンデンサと、
を備え、
前記第2のスナバコンデンサは、その接続位置から前記第1のスナバコンデンサの接続位置までの間の配線インダクタンス成分よりも、その接続位置から前記過電流保護素子までの配線インダクタンス成分と当該過電流保護素子のインダクタンス成分との和の方が大きくなるように接続されていることを特徴とする電力変換器。 In a power converter provided with an overcurrent protection element in each of a high potential side DC line and a low potential side DC line between a smoothing capacitor and an SiC power module constituting an inverter circuit,
A first snubber capacitor connected to a terminal portion of the SiC power module;
A second snubber capacitor connected between the high potential side DC line and the low potential side DC line between the overcurrent protection element and the inverter circuit;
With
The second snubber capacitor has a wiring inductance component from the connection position to the overcurrent protection element and the overcurrent protection rather than a wiring inductance component from the connection position to the connection position of the first snubber capacitor. A power converter characterized by being connected so that the sum of the inductance component of the elements is larger. - 平滑コンデンサと、インバータ回路を構成するSiCパワーモジュールとの間の高電位側直流ラインおよび低電位側直流ラインのそれぞれに過電流保護素子を設けた電力変換器において、
前記SiCパワーモジュールの端子部に第1のスナバコンデンサを接続し、かつ、前記過電流保護素子における前記インバータ回路側の各端子部の間に第2のスナバコンデンサを接続したことを特徴とする電力変換器。 In the power converter in which an overcurrent protection element is provided in each of the high potential side DC line and the low potential side DC line between the smoothing capacitor and the SiC power module constituting the inverter circuit,
A first snubber capacitor is connected to a terminal portion of the SiC power module, and a second snubber capacitor is connected between each terminal portion on the inverter circuit side in the overcurrent protection element. converter. - 前記第2のスナバコンデンサの容量値が前記第1のスナバコンデンサの容量値よりも大きい値に設定されていることを特徴とする請求項1または2に記載の電力変換器。 The power converter according to claim 1 or 2, wherein a capacitance value of the second snubber capacitor is set to be larger than a capacitance value of the first snubber capacitor.
- 前記過電流保護素子と前記第2のスナバコンデンサとによりLCフィルタが構成されるように、前記第2のスナバコンデンサの容量値を選定することを特徴とする請求項1乃至3の何れか1項に記載の電力変換器。 4. The capacitance value of the second snubber capacitor is selected so that an LC filter is configured by the overcurrent protection element and the second snubber capacitor. 5. The power converter as described in.
- 前記SiCパワーモジュールの端子部もしくは内部に高周波対策用のRCスナバ回路が設けられていることを特徴とする請求項1乃至4の何れか1項に記載の電力変換器。 The power converter according to any one of claims 1 to 4, wherein an RC snubber circuit for high-frequency countermeasures is provided in a terminal portion or inside of the SiC power module.
- 前記第1および第2のスナバコンデンサの少なくとも一つがRDCスナバ回路として構成されていることを特徴とする請求項1乃至3の何れか1項に記載の電力変換器。 The power converter according to any one of claims 1 to 3, wherein at least one of the first and second snubber capacitors is configured as an RDC snubber circuit.
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JP2018170852A (en) * | 2017-03-29 | 2018-11-01 | 住友重機械工業株式会社 | Power component |
CN111404128A (en) * | 2020-03-18 | 2020-07-10 | 无锡赛思亿电气科技有限公司 | Simulation modeling analysis method for analyzing response capability of fuse in frequency converter of direct-current power system to short-circuit current |
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JP2018170852A (en) * | 2017-03-29 | 2018-11-01 | 住友重機械工業株式会社 | Power component |
CN111404128A (en) * | 2020-03-18 | 2020-07-10 | 无锡赛思亿电气科技有限公司 | Simulation modeling analysis method for analyzing response capability of fuse in frequency converter of direct-current power system to short-circuit current |
CN111404128B (en) * | 2020-03-18 | 2021-03-16 | 无锡赛思亿电气科技有限公司 | Simulation modeling analysis method for analyzing response capability of fuse in frequency converter of direct-current power system to short-circuit current |
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