Multiphase motor generator system and control method thereof

Patent metadata

Field	Value
Publication number	US-9571024-B1
Application number	US-201614987987-A
Country	US
Kind code	B1
Filing date	Jan 5, 2016
Priority date	Jan 5, 2016
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A multiphase motor generator system includes a multiphase induction motor having a plurality of separate terminals, a multiphase inverter coupled to a DC link voltage source and the plurality of terminals of the multiphase induction motor, a plurality of current detectors configured to detect a plurality of currents that flow between the multiphase inverter and the plurality of terminals of the multiphase induction motor, and a controller coupled to the current detectors and the multiphase inverter, and configured to receive the detected currents and output a plurality of control voltages to the multiphase inverter. The controller includes a multiphase to direct-quadrature (dq) conversion unit, a dq equivalent unit, a dq to multiphase conversion unit, and a pulse-width-modulator (PWM) converter.

First claim

What is claimed is:

1. A multiphase motor generator system, comprising:
a multiphase induction motor having a plurality of separate terminals;
a multiphase inverter coupled to a DC link voltage source and the plurality of terminals of the multiphase induction motor;
a plurality of current detectors configured to detect a plurality of currents that flow between the multiphase inverter and the plurality of terminals of the multiphase induction motor; and
a controller coupled to the current detectors and the multiphase inverter, and configured to receive the detected currents and output a plurality of control voltages to the multiphase inverter, the controller including:
a multiphase to direct-quadrature (dq) conversion unit configured to convert the plurality of currents into a direct-axis (d-axis) current value I d and a quadrature-axis (q-axis) current value I q in a rotating reference system;
a dq equivalent unit configured to determine a d-axis voltage command value V* d and a q-axis voltage command value V* q based on the d-axis current value I d and the q-axis current value I q ;
a dq to multiphase conversion unit configured to convert the d-axis voltage command value V* d and the q-axis voltage command value V* q into a plurality of command voltages; and
a pulse-width-modulator (PWM) converter configured to convert the plurality of command voltages to the plurality of control voltages, and apply the plurality of control voltages to the multiphase inverter;

wherein the multiphase induction motor is an n-phase induction motor, with n being an integer that is multiple of 3,
the multiphase to dq conversion unit being configured to:
project n currents i p1 , i p2 , . . . , and i pn onto an α-axis and a β-axis in a stationary reference system to generate an α-axis current i α and a β-axis current i β represented by the following equation,

[

i
α

i
β

0

]

=

2
n

⁡

[

cos
⁡

(

0
·

P
2

·

2
⁢
π

n

)

cos
⁡

(

1
·

P
2

·

2
⁢
π

n

)

cos
⁡

(

2
·

P
2

·

2
⁢
π

n

)

…

sin
⁡

(

0
·

P
2

·

2
⁢
π

n

)

sin
⁡

(

1
·

P
2

·

2
⁢
π

n

)

sin
⁡

Assignees

• Caterpillar Inc

Inventors

• Yuan Chen
• Ramamoorthy Krishnakumar Dharapuram
• Alkhouli Osama Mohammad

Classifications

• H02P27/08

  with pulse width modulation · CPC title

• H02P21/0035 Primary

  Electricity · mapped topic

• H02P21/09 Primary

  Field phase angle calculation based on rotor voltage equation by adding slip frequency and speed proportional frequency · CPC title

• H02P2207/01

  Asynchronous machines · CPC title

• H02P25/22

  Multiple windings; Windings for more than three phases · CPC title