Power conversion device
阅读说明：本技术 电力变换装置 (Power conversion device ) 是由 菅原烈 粟根和俊 于 2018-02-16 设计创作，主要内容包括：电容器(C)具有寄生电感分量(Lp),在正极线(PL1)与负极线(NL)之间电连接。转换器(10)构成为包括设置于正极线(PL1)的电抗器(Lc),进行通过电容器(C1)平滑化后的直流电压的电压变换。逆变器(20)构成为通过开关控制进行转换器(10)与交流马达(M)之间的直流交流变换。正极线(PL1)中的连接直流电源(B)和电容器(C)的路径(PATH1)的电感小于负极线(NL)中的连接直流电源(B)和电容器(C)的路径(PATH2)的电感。路径(PATH2)的电感和路径(PATH1)的电感的差小于寄生电感分量(Lp)的2倍。(The capacitor (C) has a parasitic inductance component (Lp) and is electrically connected between a positive line (PL1) and a Negative Line (NL). The converter (10) is configured to include a reactor (Lc) provided on a positive line (PL1), and performs voltage conversion of the DC voltage smoothed by a capacitor (C1). The inverter (20) is configured to perform DC/AC conversion between the converter (10) and the AC motor (M) by switching control. The inductance of a PATH (PATH1) connecting the dc power supply (B) and the capacitor (C) in the positive line (PL1) is smaller than the inductance of a PATH (PATH2) connecting the dc power supply (B) and the capacitor (C) in the Negative Line (NL). The difference between the inductance of the PATH (PATH2) and the inductance of the PATH (PATH1) is less than 2 times the parasitic inductance component (Lp).)
1. A power conversion device is provided with:
a positive electrode terminal and a negative electrode terminal that receive power supplied from a DC power supply;
a 1 st power line configured to be electrically connectable to one of the positive electrode terminal and the negative electrode terminal;
a 2 nd power line configured to be electrically connectable to the other of the positive electrode terminal and the negative electrode terminal;
a smoothing capacitor having a parasitic inductance component, electrically connected between the 1 st power line and the 2 nd power line;
a converter configured to include a reactor provided in the 1 st power line, the converter performing voltage conversion of the dc voltage smoothed by the smoothing capacitor; and
an inverter configured to perform DC/AC conversion between the converter and an AC load by switching control,
an inductance of a 1 st path connecting the one of the positive electrode terminal and the negative electrode terminal and the smoothing capacitor in the 1 st power line is smaller than an inductance of a 2 nd path connecting the other of the positive electrode terminal and the negative electrode terminal and the smoothing capacitor in the 2 nd power line,
the difference between the inductance of the 2 nd path and the inductance of the 1 st path is less than 2 times the parasitic inductance component of the smoothing capacitor.
2. The power conversion device according to claim 1,
further comprises an inductor disposed on the 2 nd path,
the inductance of the inductor is less than 2 times the parasitic inductance component of the smoothing capacitor.
3. The power conversion device according to claim 1,
the inductance of the 2 nd path is a parasitic inductance component of the 2 nd path,
the parasitic inductance component of the 2 nd path is less than 2 times the parasitic inductance component of the smoothing capacitor.
4. The power conversion device according to claim 1, further comprising:
a 1 st inductor disposed on the 1 st path; and
a 2 nd inductor disposed on the 2 nd path,
the difference between the inductance of the 2 nd inductor and the inductance of the 1 st inductor is less than 2 times the parasitic inductance component of the smoothing capacitor.
5. A power conversion device is provided with:
a positive electrode terminal and a negative electrode terminal that receive power supplied from a DC power supply;
a 1 st power line configured to be electrically connectable to one of the positive electrode terminal and the negative electrode terminal;
a 2 nd power line configured to be electrically connectable to the other of the positive electrode terminal and the negative electrode terminal;
a smoothing capacitor having a parasitic resistance component and electrically connected between the 1 st power line and the 2 nd power line;
a converter configured to include a reactor electrically connected to the 1 st power line, the converter performing voltage conversion; and
an inverter configured to perform DC/AC conversion between the converter and an AC load by switching control,
a resistance of a 1 st path connecting the one of the positive electrode terminal and the negative electrode terminal and the smoothing capacitor in the 1 st power line is smaller than a resistance of a 2 nd path connecting the other of the positive electrode terminal and the negative electrode terminal and the smoothing capacitor in the 2 nd power line,
the difference between the resistance of the 2 nd path and the resistance of the 1 st path is less than 2 times the parasitic resistance component of the smoothing capacitor.
Technical Field
The present invention relates to a power conversion device that performs power conversion between a dc power supply and an ac load, and more particularly to a power conversion device that includes a converter including a reactor and performs power conversion between a dc power supply and an ac load.
Background
There is known a power converter configured to perform power conversion between a dc power supply and an ac load by switching control. In switching control at a high frequency (for example, a frequency of 20kHz or higher), high-frequency noise (switching noise) may occur due to switching operation of switching elements of an inverter in a power conversion device. The mechanism of occurrence of this switching noise is explained below. That is, the neutral point potential of the ac load (for example, an ac motor) fluctuates due to the switching operation of the inverter, and thereby common mode noise occurs.
In the case where the circuit configuration of the power conversion device is unbalanced on the positive side and the negative side, mode conversion between common mode noise (common mode noise) and normal mode noise (normal mode noise) may be caused. That is, there is a possibility that the common mode noise is converted into the normal mode noise or the normal mode noise is converted into the common mode noise. Therefore, a technique for reducing switching noise by preventing mode switching has been proposed.
For example, a power conversion device disclosed in japanese patent laid-open No. 2009-296756 (patent document 1) includes loop 1 and loop 2 circuits. The 1 st loop circuit includes a midpoint tap of the 2 nd-side coil, a capacitor, a Y capacitor on the high potential side, a high potential side wiring, and a high potential side switching element. On the other hand, the 2 nd loop circuit includes a midpoint tap, a capacitor, a low-potential-side Y capacitor, a low-potential-side wiring, and a low-potential-side switching element. In the power converter disclosed in patent document 1, a midpoint tap is connected to a connection point between a high-potential side Y capacitor and a low-potential side Y capacitor. Thus, the impedance of the 1 st loop circuit and the impedance of the 2 nd loop circuit are equal. As a result, the imbalance of the power converter is eliminated, and therefore, the mode conversion can be prevented (see, for example, paragraph [0038] of patent document 1).
Disclosure of Invention
The power conversion device disclosed in patent document 1 is a device that steps down the voltage of a high-voltage battery (for example, several hundred volts) and outputs the voltage to a low-voltage battery (for example, a 12V battery), and has a configuration including an insulated converter including a transformer (see, for example, paragraphs [0028] to [0032] and fig. 1 in patent document 1).
On the other hand, in the power conversion apparatus, an example of a configuration including a converter including a reactor has been widely put into practical use. Patent document 1 does not particularly mention a configuration including such a converter, and no study is made on reduction of switching noise in this configuration. In a power converter having a configuration including a converter including a reactor, it is also desired to suitably reduce switching noise.
The present invention has been made to solve the above-described problems, and an object of the present invention is to suitably reduce switching noise in a power conversion device that includes a converter including a reactor and performs power conversion between a dc power supply and an ac load.
(1) A power conversion device according to an aspect of the present invention includes a positive electrode terminal and a negative electrode terminal, 1 st and 2 nd power lines, a smoothing capacitor, a converter, and an inverter. The positive electrode terminal and the negative electrode terminal receive electric power supplied from a dc power supply. The 1 st power line is electrically connectable to one of the positive electrode terminal and the negative electrode terminal. The 2 nd power line is electrically connectable to the other of the positive electrode terminal and the negative electrode terminal. The smoothing capacitor has a parasitic inductance component and is electrically connected between the 1 st power line and the 2 nd power line. The converter includes a reactor provided on the 1 st power line, and performs voltage conversion of the dc voltage smoothed by the smoothing capacitor. The inverter is configured to perform dc/ac conversion between the converter and the ac load by switching control. The inductance of the 1 st path connecting the one of the positive and negative terminals and the smoothing capacitor in the 1 st power line is smaller than the inductance of the 2 nd path connecting the other of the positive and negative terminals and the smoothing capacitor in the 2 nd power line. The difference between the inductance of the 2 nd path and the inductance of the 1 st path is less than 2 times the parasitic inductance component of the smoothing capacitor.
(2) Preferably, the power conversion device further includes an inductor provided in the 2 nd path. The inductance of the inductor is less than 2 times the parasitic inductance component of the smoothing capacitor.
(3) Preferably, the inductance of path2 is a parasitic inductance component of
(4) Preferably, the power conversion device further includes a 1 st inductor provided in the 1 st path and a 2 nd inductor provided in the 2 nd path. The difference between the inductance of the 2 nd inductor and the inductance of the 1 st inductor is less than 2 times the parasitic inductance component of the smoothing capacitor.
(5) In a power converter according to an aspect of the present invention, the power converter includes a positive electrode terminal, a negative electrode terminal, 1 st and 2 nd power lines, a smoothing capacitor, a converter, and an inverter. The positive electrode terminal and the negative electrode terminal receive electric power supplied from a dc power supply. The 1 st power line is electrically connectable to one of the positive electrode terminal and the negative electrode terminal. The 2 nd power line is electrically connectable to the other of the positive electrode terminal and the negative electrode terminal. The smoothing capacitor has a parasitic resistance component and is electrically connected between the 1 st power line and the 2 nd power line. The converter includes a reactor provided on the 1 st power line, and performs voltage conversion of the dc voltage smoothed by the smoothing capacitor. The inverter is configured to perform dc/ac conversion between the converter and the ac load by switching control. The resistance of the 1 st path connecting the one of the positive and negative terminals and the smoothing capacitor in the 1 st power line is smaller than the resistance of the 2 nd path connecting the other of the positive and negative terminals and the smoothing capacitor in the 2 nd power line. The difference between the resistance of the 2 nd path and the resistance of the 1 st path is less than 2 times the parasitic resistance component of the smoothing capacitor.
According to the present invention, in a power conversion device that includes a converter including a reactor and performs power conversion between a dc power supply and an ac load, switching noise can be reduced appropriately.
Drawings
Fig. 1 is a circuit block diagram schematically showing the configuration of a power conversion device according to a comparative example.
Fig. 2 is a diagram for explaining a mechanism of generation and a mechanism of conversion of noise in the power converter according to the comparative example.
Fig. 3 is a circuit block diagram schematically showing the configuration of the power conversion device according to embodiment 1.
Fig. 4 is a diagram for explaining a noise transmission path in the power converter according to embodiment 1.
Fig. 5 is a diagram showing an example of the correlation between the inductance of the inductor L and the conversion ratio.
Fig. 6 is a diagram showing an example of analysis results for explaining the noise reduction effect of the power conversion device according to embodiment 1.
Fig. 7 is a circuit block diagram schematically showing the configuration of a power conversion device according to a modification of embodiment 1.
Fig. 8 is a circuit block diagram schematically showing the configuration of the power conversion device according to
(description of reference numerals)
1. 1A, 2, 9: a power conversion device; 10: a converter; 20: an inverter; 31. 32: a voltage sensor; 33: a current sensor; 100: a control device; b: a direct current power supply; c1, C2: a capacitor; D1-D8: a diode; I. in, Ip: current flow; l, La, Lb: an inductor; lc: a reactor; lp: a parasitic inductance component; m: an AC motor; PL1, PL 2: a positive line; NL: a negative electrode line; Q1-Q8: a switching element; r: a resistance; and Rp: a parasitic resistance component; tn: a negative terminal; tp: a positive terminal; tu: a U-phase terminal; tv: a V-phase terminal; tw: and a W-phase terminal.
Detailed Description
Hereinafter, the embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated.