On-board electric compressor with a motor and noise reducing unit with inverter device having a damping unit reducing Q value of low pass filter circuit

Patent metadata

Field	Value
Publication number	US-11025141-B2
Application number	US-201716088362-A
Country	US
Kind code	B2
Filing date	Mar 30, 2017
Priority date	Mar 31, 2016
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

An on-board electric compressor that comprises: a housing; a compression unit; an electric motor; and an inverter device. The inverter device comprises: an inverter circuit that converts direct current power to alternating current power; and a noise reduction unit that is provided on an input side of the inverter circuit and that reduces common mode noise and normal mode noise that are included in the direct current power The noise reduction unit comprises: a common mode choke coil; and a smoothing capacitor that, in cooperation with the common mode choke coil, constitutes a low pass filter circuit. The common mode choke coil has: a core that has a first core part and a second core part; a first winding that is wound around the first core part; and a second winding that is wound around the second core part.

First claim

The invention claimed is:

1. An on-board motor-driven compressor comprising:
a housing including a suction port through which fluid is drawn in;
a compression unit accommodated in the housing and configured to compress the fluid;
an electric motor accommodated in the housing and configured to drive the compression unit; and
an inverter device configured to drive the electric motor, wherein the inverter device includes
an inverter circuit configured to convert DC power to AC power, and
a noise reducing unit arranged at an input side of the inverter circuit and configured to reduce common mode noise and normal mode noise contained in the DC power before the DC power is input to the inverter circuit, wherein the noise reducing unit includes
a common mode choke coil including a core having a first core portion and a second core portion, a first winding wound around the first core portion, and a second winding wound around the second core portion, and
a smoothing capacitor that cooperates with the common mode choke coil to configure a low pass filter circuit, and
the inverter device further includes a damping unit located at a position intersecting a magnetic path of a leakage magnetic flux generated from the common mode choke coil, wherein the damping unit generates eddy current with the leakage magnetic flux to lower a Q value of the low pass filter circuit.

2. The on-board motor-driven compressor according to claim 1 , wherein the damping unit covers at least one part of a side surface of the common mode choke coil.

3. The on-board motor-driven compressor according to claim 1 , wherein
the inverter device includes
a circuit board including a wire pattern, and
an inverter case accommodating the inverter circuit, the circuit board, and the noise reducing unit; and
the damping unit is box-shaped and includes an opening covered by the inverter case; and
the common mode choke coil is accommodated in an accommodation compartment defined by the damping unit and the inverter case.

4. The on-board motor-driven compressor according to claim 1 , wherein the damping unit includes a shield electrically conductive metal film that covers at least one part of the common mode choke coil.

5. The on-board motor-driven compressor according to claim 1 , wherein the damping unit is made of an electrically conductive material of a non-magnetic body.

6. The on-board motor-driven compressor according to claim 1 , wherein
the low pass filter circuit has a specific Q value when a gain of the low pass filter circuit with respect to the normal mode noise having a frequency that is the same as a resonance frequency of the low pass filter circuit is a tolerable gain set based on a specification of a vehicle; and
the damping unit is configured to lower a Q value of the low pass filter circuit from the specific Q value.

7. The on-board motor-driven compressor according to claim 1 , wherein the damping unit covers the common mode choke coil to form a closed loop.

8. The on-board motor-driven compressor according to claim 1 , wherein
the first winding and the second winding are opposed to each other and have winding axes extending in a same direction, and
the damping unit covers the first and second windings in a direction orthogonal to a winding axis direction of the first and second windings.

9. The on-board motor-driven compressor according to claim 1 , wherein the core includes:
an exposed portion where the first and second windings are not wound and a surface of the core is exposed, and
a peripheral core surface, the peripheral core surface being a first plane intersecting a second plane including winding axes of the first and second windings, and
wherein the damping unit covers a portion of the peripheral core surface where the first and second windings are wound, without covering a portion including the exposed portion of the peripheral core surface.

10. The on-board motor-driven compressor according to claim 1 , wherein
the inverter device includes a circuit board including a wire pattern; and
the damping unit includes
a shield electrically conductive metal case including an opening, wherein the common mode choke coil is accommodated in the shield electrically conductive metal case through the opening, and the shield electrically conductive metal case is fixed to the circuit board so as to close the opening with the circuit board, and
a shield electrically conductive metal film formed in a region at an inner side of the opening on the circuit board.

11. The on-board motor-driven compressor according to claim 10 , wherein the shield electrically conductive metal film is a shield pattern conductor.

Assignees

• Toyota Jidoshokki Kk

Inventors

• Kagawa Fumihiro
• Naito Atsushi
• Nagata Yoshiki
• Ambo Shunsuke
• Yashiro Keiji
• Shiraishi Kazuhiro

Classifications

• H02K11/01

  for shielding from electromagnetic fields {, i.e. structural association with shields} (means for preventing or reducing eddy-current losses in the winding heads by shielding H02K3/42) · CPC title

• H02M1/123

  Suppression of common mode voltage or current · CPC title

• H02M1/0064

  Magnetic structures combining different functions, e.g. storage, filtering or transformation · CPC title

• H03H7/0115

  comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) · CPC title

• H02K2211/03

  Machines characterised by circuit boards, e.g. pcb · CPC title