Motor-driven compressor

Patent metadata

Field	Value
Publication number	US-10087935-B2
Application number	US-201615247109-A
Country	US
Kind code	B2
Filing date	Aug 25, 2016
Priority date	Aug 28, 2015
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

A motor-driven compressor includes a three-phase motor including a rotor, a housing, a compression unit, a drive circuit, and a controller. The drive circuit includes u-phase upper and lower arm switching elements, v-phase upper and lower arm switching elements, and w-phase upper and lower arm switching elements. The controller performs a deceleration control in response to the rotor being rotating in a direction opposite to the forward direction. The controller controls the drive circuit in a switching control mode that includes a first mode, in which one or more switching elements of the upper and lower arm switching elements of the three phases are activated while the remaining switching elements are deactivated, and a second mode, which differs from the first mode in a combination of the activated and deactivated switching elements.

First claim

The invention claimed is:

1. A motor-driven compressor comprising:
a three-phase motor including a rotor;
a housing including a suction port that draws in a fluid;
a compression unit driven by the three-phase motor, wherein the compression unit compresses an intake fluid, which is the fluid drawn in from the suction port, and discharges a compressed fluid, which is the compressed intake fluid;
a drive circuit that drives the three-phase motor; and
a controller that controls the drive circuit, wherein
the compression unit includes
a fixed scroll fixed to the housing,
a movable scroll engaged with the fixed scroll and configured to orbit the fixed scroll, and
a compression chamber defined by the fixed scroll and the movable scroll,

when the rotor rotates in a predetermined forward direction, the movable scroll orbits in the forward direction, and the compression unit thereby compresses the intake fluid drawn into the compression chamber,
the motor-driven compressor further comprises an injection port that draws an intermediate pressure fluid into the compression chamber, wherein the intermediate pressure fluid has a pressure that is higher than the intake fluid and lower than the compressed fluid,
the drive circuit includes
a u-phase upper arm switching element and a u-phase lower arm switching element connected to each other,
a v-phase upper arm switching element and a v-phase lower arm switching element connected to each other, and
a w-phase upper arm switching element and a w-phase lower arm switching element connected to each other,

the controller is configured to perform a deceleration control that decelerates the rotor in response to the rotor being rotating in a direction opposite to the forward direction, and
in the deceleration control, the controller is configured to control the drive circuit in a switching control mode that includes a first mode, in which one or more switching elements of the upper arm switching elements of the three phases and the lower arm switching elements of the three phases are activated while the remaining switching elements are deactivated, and a second mode, which differs from the first mode in a combination of the activated and deactivated switching elements.

2. The motor-driven compressor according to claim 1 , wherein the switching control mode in the deceleration control includes one of
a mode that switches the upper arm switching elements of the three phases to sequentially switch the upper arm switching element that is activated,
a mode that switches the lower arm switching elements of the three phases to sequentially switch the lower arm switching element that is activated, and
a mode that switches the upper arm switching elements of the three phases and the lower arm switching elements of the three phases to sequentially switch the switching element that is activated without simultaneously activating the upper arm switching element and the lower arm switching element of the same phase.

3. The motor-driven compressor according to claim 2 , further comprising a recognition unit that recognizes a rotation direction of the rotor and a rotational frequency of the rotor,
wherein in the deceleration control, the controller is configured to variably control at least one of a switching pattern and a duty ratio of subject arm switching elements of the three phases, which are subject to switching in the deceleration control, based on the rotational frequency recognized by the recognition unit so that a current flowing to the three-phase motor does not exceed a predetermined tolerance value.

4. The motor-driven compressor according to claim 3 , wherein
the switching pattern includes
a one-phase pattern that includes a mode in which the subject arm switching element of one of the three phases is activated while the subject arm switching elements of the remaining two phases are deactivated, wherein in the one-phase pattern, the subject arm switching elements of multiple phases are not simultaneously activated, and
a two-phase pattern that includes a mode in which the subject arm switching elements of two of the three phases are activated while the subject arm switching element of the remaining phase is deactivated, and

the controller is configured to set the switching pattern to the one-phase pattern when the rotational frequency is greater than or equal to a predetermined threshold value and the two-phase pattern when the rotational frequency is less than the threshold value.

5. The motor-driven compressor according to claim 3 , wherein the controller is configured to increase the duty ratio as the rotational frequency decreases.

6. The motor-driven compressor according to claim 3 , wherein the recognition unit recognizes the rotation direction of the rotor and the rotational frequency of the rotor based on a current that flows to the three-phase motor under the deceleration control.

7. The motor-driven compressor according to claim 3 , wherein the controller is configured to select the switching pattern and the duty ratio that have a tendency to increase a current flowing to the three-phase motor as the rotational frequency decreases.

8. The motor-driven compressor according to claim 1 , wherein the motor-driven compressor is installed in a vehicle and used with a vehicle air conditioner.

Assignees

• Toyota Jidoshokki Kk

Inventors

• Ichihara Akimitsu
• Kawamura Shinichi
• Kawashima Takashi

Classifications

• F04C2240/403

  with inverter for speed control · CPC title

• F04C28/28

  Safety arrangements; Monitoring · CPC title

• F04C28/06 Primary

  specially adapted for stopping, starting, idling or no-load operation · CPC title

• F04C2210/26

  Refrigerants with particular properties, e.g. HFC-134a · CPC title

• F04C29/0092

  Removing solid or liquid contaminants from the gas under pumping, e.g. by filtering or deposition; Purging; Scrubbing; Cleaning · CPC title