Method and system for driving electric machines

Patent metadata

Field	Value
Publication number	US-9325273-B2
Application number	US-201314040767-A
Country	US
Kind code	B2
Filing date	Sep 30, 2013
Priority date	Sep 30, 2013
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A system for driving an electric machine is provided. The system includes a power converter coupled to an input source and the electric machine. The power converter includes a leg that includes a first and second string. The first string includes plurality of controllable semiconductor switches, a first and second connecting node. The first string is operatively coupled across a first and second bus. The second string is operatively coupled to the first string via the first and second connecting node. The second string comprises plurality of switching modules. The switching modules include fully controllable semiconductor switches and energy storage devices. The system further includes a system controller configured to provide activation commands to the controllable semiconductor switches and the switching modules such that energy stored in the energy storage device is provided to the electric machine when the machine is switched on for operation.

First claim

The invention claimed is:

1. A system for driving an electric machine, the system comprising:
a power converter coupled to an input source and the electric machine, the power converter comprising:
at least one power converter leg, each leg comprising:
a first string comprising a plurality of controllable semiconductor switches, a first connecting node, and a second connecting node, wherein the first string is operatively coupled to the input source across a first DC bus and a second DC bus , wherein at least one of the controllable semiconductor switches is situated between the first connecting node and the first DC bus, and wherein at least one other of the controllable semiconductor switches is situated between the second connecting node and the second DC bus; and
a second string operatively coupled to the first string via the first connecting node and the second connecting node, wherein the second string comprises a plurality of switching modules, wherein each of the plurality of switching modules comprises a plurality of fully controllable semiconductor switches and at least one energy storage device coupled in series across the plurality of fully controllable semiconductor switches, wherein the second string is operably coupled to the electric machine; and

a system controller configured to provide activation commands to at least some of the controllable semiconductor switches from the first string, and at least some of the switching modules from the second string such that energy stored in at least one of the at least one energy storage devices of the plurality of switching modules is provided to the electric machine when the electric machine is switched on for operation.

2. The system as recited in claim 1 , wherein the first string comprises a first branch and a second branch that are operatively coupled via a third connecting node.

3. The system as recited in claim 2 , wherein the third connecting nodes of each of the legs are connected to a third DC bus.

4. The system as recited in claim 3 , wherein the system controller is configured to provide activation commands such that at least one leg of the power converter is coupled to the first DC bus and at least one leg of the power converter is coupled to the second DC bus when the energy in the energy storage device is below a predetermined threshold value.

5. The system as recited in claim 4 , wherein the system controller is configured to provide activation commands such that each leg of the power converter is coupled to the third DC bus when the electric machine is activated.

6. The system as recited in claim 1 , wherein each of the switching modules comprise a half-bridge configuration.

7. The system as recited in claim 1 , wherein the second string comprises a first arm operatively coupled to a second arm.

8. The system as recited in claim 7 , wherein the system controller is configured to balance energy stored in the first arm and the second arm.

9. The system as recited in claim 1 wherein the electric machine comprises an electric motor.

Assignees

• Gen Electric

Inventors

• Zhang Di
• Garcés Luis José
• Rockhill Andrew Allen
• Lai Rixin

Classifications

• H02P27/14 Primary

  with three or more levels of voltage · CPC title

• H02M7/217 Primary

  using semiconductor devices only · CPC title

• H02P27/06 Primary

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• H02M7/487

  Neutral point clamped inverters · CPC title

• H02M2007/4835

  Electricity · mapped topic