Inverter and motor

Details Inverter and motor Inverter and motor

2000-05-12

2001-05-22

Nguyen, Matthew (Department: 2838)

Electric power conversion systems

Current conversion

Using semiconductor-type converter

C363S098000, C318S801000

Reexamination Certificate

active

06236583

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a combination of an alternating current motor and an inverter which supplies a drive current to the alternating current motor.
BACKGROUND OF THE INVENTION
An inverter is known which, in order to obtain an alternating current which drives an alternating current motor, changes a direct current into an alternating current of a predetermined frequency and voltage.
The direct current is obtained from a battery or by rectifying an alternating current using a converter or a rectifier circuit.
SUMMARY OF THE INVENTION
In an alternating current motor operated by the output of such an inverter, the voltage of the neutral point of a coil is changed according to switching timings of switching elements of the inverter. This change generates a high frequency leakage current, so if such an alternating current motor is used for driving a vehicle, noise is generated which affects instruments mounted on the vehicle, e.g., the radio.
If a noise filter comprising a common mode reactor is inserted in the input circuit and output circuit of the inverter, the high frequency leakage current of the motor may decrease, but a sufficient effect is not necessarily achieved. Moreover, due to the volume and weight of the reactor, the volume and weight of the inverter necessarily increase which makes it unsuitable for installation in a vehicle with limited space. Further, since the reactor is expensive, the cost of the inverter also rises.
It is therefore an object of this invention to control the occurrence of the high frequency leakage current in an alternating current motor due to inverter current without using a noise filter.
It is another object of this invention to improve the motor efficiency of an alternating current motor which is operated by the output current from an inverter.
It is yet another object of this invention to provide a combination of a lightweight, compact inverter without high frequency leakage current, and an alternating current motor.
It is yet another object of this invention to suppress the torque ripple of an alternating current motor.
In order to achieve the above objects, this invention provides a motor and an inverter which drives the motor, wherein the motor and the inverter have following constructions.
The motor comprises a stator and a rotor. The stator comprises plural groups of windings, each of which has coils and generates a rotating magnetic field according to the energization of the coils of each group. The rotor rotates due to the rotating magnetic fields of the plural groups of windings.
The inverter comprises an identical number of switching circuits to the number of groups. Each of the circuits comprises plural switching elements and supplying alternating current to the coils of each group according to the switching action of the plural switching elements. The inverter further comprises a control unit which controls the switching elements of the switching circuits corresponding to each group so that the sum of terminal voltages of the coils of each group is constant.
This invention also provides a three-phase alternating current motor and an inverter which drives the motor, wherein the motor and the inverter have following constructions.
The motor comprises a stator and a motor. The stator generates a rotating magnetic field according to the supply of a three-phase alternating current to a first winding, second winding and third winding corresponding to each phase of the three-phase alternating current. The rotor rotates according to the rotating magnetic field of the stator.
The inverter comprises a first switching circuit which supplies alternating current to the first winding according to a switching action of plural switching elements, a second switching circuit which supplies alternating current to the second winding according to a switching action of plural switching elements, and a third switching circuit which supplies alternating current to the third winding according to a switching action of plural switching elements. The inverter further comprises a control unit which controls the switching elements of the first switching circuit, the switching elements of the second switching circuit, and the switching elements of the third switching circuit so that the sum of a terminal voltage of the first winding, a terminal voltage of the second winding and a terminal voltage of the third winding is constant.


REFERENCES:
patent: 5008801 (1991-04-01), Glennon
patent: 5414339 (1995-05-01), Masaki et al.
patent: 5717584 (1998-02-01), Rajashekara et al.

Affiliated with

Also associated with

Rating

Inverter and motor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Inverter and motor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inverter and motor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2457929