Reverse rotation braking for a PM motor

Patent metadata

Field	Value
Publication number	US-9525369-B2
Application number	US-201514665402-A
Country	US
Kind code	B2
Filing date	Mar 23, 2015
Priority date	Aug 17, 2011
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

A system includes a motor, an inverter bridge, a voltage detection circuit, and a controller. The motor has a stator and a rotor. The inverter bridge is configured to provide a voltage to the stator, and includes a first switch connected in a series-type relationship with a second switch, a first diode coupled across the first switch, and a second diode coupled across the second switch. The voltage detection circuit is configured to detect a back EMF voltage in the winding. The controller is configured to control the first switch and the second switch to drive the motor, and to receive an indication of the back EMF voltage in the winding from the voltage detection circuit. The controller is also configured to determine a fault has occurred, and to drive one of the first switch and the second switch when a fault has occurred.

First claim

What is claimed is:

1. A system for operating a compressor, the system comprising:
a motor having a winding and a rotor;
an inverter bridge configured to provide a voltage to the winding, the inverter bridge including a first switch connected in a series-type relationship with a second switch, a first diode coupled across the first switch, and a second diode coupled across the second switch;
a voltage detection circuit configured to detect a back EMF voltage value in the winding; and
a controller coupled to the inverter bridge and the voltage detection circuit, the controller configured to control the first switch and the second switch to drive the motor, configured to receive the back EMF voltage value in the winding from the voltage detection circuit, configured to determine a fault has occurred when the detected back EMF voltage value in the winding equals about zero, by a condition indicative of reverse rotation, and configured to drive one of the first switch and the second switch on when a fault has occurred is determined, so as to induce a voltage in the winding and cause a short circuit current to flow,
wherein driving one of the first switch and the second switch on causes the short circuit current to exert a braking force on the rotor,
wherein the braking force reduces a rate at which the rotor rotates, prevents the motor from producing a voltage and a current sufficient to damage components of the system, and reduces reverse rotation of the motor, and
wherein the braking force stops the rotor from rotating.

2. The system of claim 1 , wherein the motor includes a second winding, the system further comprising a second inverter bridge configured to provide a voltage to the second winding, the second inverter bridge including a third switch connected in a series-type relationship with a fourth switch, a third diode coupled across the third switch, and a fourth diode coupled across the fourth switch.

3. The system of claim 2 , wherein the controller is further configured to drive the first switch and the third switch or the second switch and the fourth switch when a fault has occurred.

4. The system of claim 3 , wherein the motor includes a third winding, the system further comprising a third inverter bridge configured to provide a voltage to the third winding, the third inverter bridge including a fifth switch connected in a series-type relationship with a sixth switch, a fifth diode coupled across the fifth switch, and a sixth diode coupled across the sixth switch.

5. The system of claim 4 , wherein the controller is further configured to drive the first switch, the third switch, and the fifth switch or the second switch, the fourth switch, and the sixth switch when a fault has occurred.

6. The system of claim 1 , wherein the first switch and the second switch are insulated gate bipolar transistors (IGBT).

7. A method of reducing a reverse rotation of a motor driving a compressor, the method comprising:
detecting a back EMF voltage value of a winding of the motor;
determining that a fault has occurred when the detected back EMF voltage value in the winding equals about zero, by a condition indicative of reverse rotation; and
driving one of a first switch and a second switch on continuously when the fault is detected to induce a voltage in the winding and cause a short circuit current to flow,
wherein driving one of the first switch and the second switch on includes the short circuit current exerting a braking force on the rotor,
wherein the braking force reduces a rate at which the rotor rotates, prevents the motor from producing a voltage and a current sufficient to damage components of the system, and reduces reverse rotation of the motor, and
wherein the braking force stops the rotor from rotating.

8. The method of claim 7 , further comprising driving a third switch continuously when driving the first switch continuously or driving a fourth switch continuously when driving the second switch continuously.

9. The method of claim 8 , further comprising driving a fifth switch continuously when driving the first switch and the third switch continuously or driving a sixth switch continuously when driving the second switch and the fourth switch continuously.

Assignees

• Trane Int Inc

Inventors

• Foye David M
• Stefanovic Victor R

Classifications

• F04B49/06

  Control using electricity (regulating by means of floats actuating electric switches F04B49/04) · CPC title

• F04B2203/0202

  Voltage · CPC title

• H02P29/0241

  the fault being an overvoltage · CPC title

• H02P3/18

  for stopping or slowing an AC motor · CPC title

• H02P6/182

  using back-emf in windings · CPC title