Inverter device

• US 6,377,478 B1
• Filed: 05/28/1999
• Issued: 04/23/2002
• Est. Priority Date: 05/28/1999
• Status: Expired due to Term

• Current Assignee: Toshiba International Corporation (Toshiba Corporation)
• Original Assignee: Toshiba International Corporation (Toshiba Corporation)
• Inventors: Morishita, Takashi
• Primary Examiner(s): Patel, Rajnikant B.
• Application Number:
  US09/322,180
• Time in Patent Office: 1,061 Days
• Field of Search: 363/34, 363/37, 363/56, 363/40, 363/41, 323/222, 323/271, 318/801, 318/701, 307/265
• US Class Current: 363/34
• CPC Class Codes: H02P 23/06 Controlling the motor in four quadrants

Abstract

A method and apparatus for conducting regenerative braking for a motor load is disclosed wherein the load is driven by a plurality of power cells on each phase-line to the load, the plurality of power inverters comprising at least one single phase power inverter and at least one 3-phase inverter wherein the 3-phase inverter is connected across 3-phase lines. First, it is detected when the motor load is regenerating a motor load voltage. Then, each single phase inverter in each phase line is shorted out after detecting the motor load regeneration. The motor load voltage is then supplied to the 3-phase inverter. Finally, the load motor voltage is lowered by conducting regenerative braking through the 3-phase inverter.

Claims

1. A method for conducting regenerative braking for a motor load, comprising the steps of:

driving said load using a plurality of power inverters on each phase-line to the load, said plurality of power inverters comprising at least one single phase power inverter and at least one 3-phase inverter wherein the 3-phase inverter is connected across 3-phase lines;

detecting when said motor load is regenerating a motor load voltage;

shorting out each single phase inverter in each phase line after detecting the motor load regeneration;

supplying said motor load voltage to said 3-phase inverter; and

lowering said load motor voltage by conducting regenerative braking through the 3-phase inverter.

2. The method according to claim 1, wherein the 3-phase inverter changes said motor load voltage into regenerative braking using a regenerative circuit.

3. The method according to claim 2, wherein said regenerative circuit comprises GTO'"'"'s.

4. The method according to claim 2, wherein said regenerative circuit comprises SCR'"'"'s.

5. The method according to claim 1, wherein the 3-phase inverter changes the motor load voltage into regenerative braking using a discharge resistance circuit.

6. The method according to claim 2, wherein the regenerative circuit provides power back to a power grid.

7. A power drive system for driving a motor load which provides regenerative braking for the motor load, comprising:

a plurality of power inverters on each phase line of the motor load, said plurality including at least one single phase inverter and at least one 3-phase inverter wherein the 3-phase inverter is connected across the different phase lines to the motor load, wherein said at least one single phase inverter and at least one 3-phase inverter output voltage for driving the motor load

means for detecting when said motor load is regenerating a motor load voltage

means for shorting out each single phase inverter in each phase line after detecting the motor load regeneration;

means for supplying said load voltage to the 3-phase inverter; and

means for lowering said motor load voltage by conducting regenerative braking through the 3-phase inverter.

8. The power drive system according to claim 7, wherein the 3-phase inverter changes said motor load voltage into regenerative braking using a regenerative circuit.

9. The power drive system according to claim 8, wherein said regenerative circuit comprises GTO'"'"'s.

10. The power drive system according to claim 8, wherein said regenerative circuit comprises SCR'"'"'s.

11. The power drive system according to claim 7, wherein the 3-phase inverter changes the motor load voltage into regenerative braking using a discharge resistance circuit.

12. The power drive system according to claim 8, wherein the regenerative circuit provides power back to a power grid.