Power conversion device with reduced noise source current, reduced high frequency current and reduced resonance current
View Patent ↗A power conversion device includes an inverter that drives a motor; a fin that cools down the inverter; a first core including a through hole that allows passage of a positive side conductor that connects a power supply system and the inverter and a negative side conductor that grounds the inverter; a ground conductor that grounds the fin; a ground conductor that grounds a motor yoke via a capacitor; and a ground conductor including one end that is connected to the negative side conductor or the ground conductor and the other end that is grounded.
1. A power conversion device comprising:
an inverter that receives power from a power supply system and drives a motor that is connected to a first ground;
a cooler that cools down the inverter;
a first core including a through hole that allows passage of a positive side conductor that connects the power supply system and the inverter and a negative side conductor that connects the inverter to a second ground;
a first ground conductor that is connected to the negative side conductor on a side of the power supply system with respect to the first core and connects the cooler to the second ground; and
a third ground conductor connected between the negative side conductor on the side of the power supply system with respect to the first core or the first ground conductor and a third ground such that the negative side conductor on the side of the power supply system with respect to the first core and the first ground conductor have a same potential as that of the third ground.
2. The power conversion device according to claim 1 , wherein the first ground and the third ground are connected to each other.
3. The power conversion device according to claim 1 , wherein the first ground and the third ground are connected to each other via a vehicle body.
4. The power conversion device according to claim 1 , wherein the first core is arranged such that, when the inverter works as a noise source, a current path through which a current flows in and out the inverter through the cooler, the first ground conductor, and the negative side conductor passes through the first core.
5. The power conversion device according to claim 1 , further comprising:
a second ground conductor that is connected to the negative side conductor on the side of the power supply system with respect to the first core and connects the motor to the second ground in an alternating-current manner via a capacitive element,
wherein the first core is arranged such that, when the inverter works as a noise source, a current path through which a current flows in and out the inverter through the cooler, the third ground conductor, the motor, the capacitive element, the second ground conductor, and the negative side conductor passes through the first core.
6. The power conversion device according to claim 1 , further comprising a second core including a through hole that allows passage of a load conductor that connects the inverter and the motor.
7. The power conversion device according to claim 1 , further comprising:
a second ground conductor that is connected to the negative side conductor on the side of the power supply system with respect to the first core and connects the motor to the second ground in an alternating-current manner via the capacitive element; and
a second core including a through hole that allows passage of a load conductor that connects the inverter and the motor,
wherein the first core and the second core are arranged such that, when the inverter works as a noise source, a current path through which a current flows in and out the inverter through the load conductor, the motor, the capacitive element, the second ground conductor, and the negative side conductor passes through the first core and the second core.
8. The power conversion device according to claim 6 , wherein the first core and the second core are arranged such that, when the inverter works as a noise source, a current path through which a current flows in and out the inverter through the load conductor, the motor, the third ground conductor, and the negative side conductor passes through the first core and the second core.
9. The power conversion device according to claim 6 , wherein an impedance of the first core is larger than an impedance of the second core.
10. The power conversion device according to claim 7 , wherein an impedance of the first core is larger than an impedance of the second core.
11. The power conversion device according to claim 6 , wherein when a frequency of the noise source is equal to or higher than 10 kHz, a phase of the impedance of each of the first core and the second core is equal to or smaller than 80°.
12. The power conversion device according to claim 7 , wherein when a frequency of the noise source is equal to or higher than 10 kHz, a phase of the impedance of each of the first core and the second core is equal to or smaller than 80°.
13. The power conversion device according to claim 1 , wherein a casing that accommodates the inverter is connected to the third ground;
and the third ground conductor is connected to the casing that is connected to the third ground.
14. The power conversion device according to claim 1 , wherein a switching device included in the inverter is formed of a wide-bandgap semiconductor.
15. A power conversion device comprising:
an inverter that is arranged in a casing, receives power from a power supply system, and drives a motor that is connected to a first ground;
a cooler that cools down the inverter;
a first core including a through hole that allows passage of a positive side conductor that connects the power supply system and the inverter and a negative side conductor that connects the inverter to a second ground;
a first ground conductor that connects the negative side conductor on a side of the power supply system with respect to the first core and the cooler; and
a second ground conductor that connects the negative side conductor on the side of the power supply system with respect to the first core and the motor via a capacitive element,
wherein the cooler is connected to a third ground such that the cooler has a same potential as that of the third ground.
16. The power conversion device according to claim 15 , wherein the casing is connected to the third ground, and the cooler is connected to the casing.
17. The power conversion device according to claim 15 , wherein the first ground and the third ground are connected to each other.
18. The power conversion device according to claim 15 , wherein the first ground and the third ground are connected to each other via a vehicle body.
19. The power conversion device according to claim 15 , wherein a switching device included in the inverter is formed of a wide-bandgap semiconductor.
20. The power conversion device according to claim 1 , wherein the third ground conductor includes one end that is connected directly to the negative side conductor on the side of the power supply system or directly to the first ground conductor with respect to the first core, and another end that is connected to the third ground.