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Integrated Brake Disclosure Number: IPCOM000236086D
Publication Date: 2014-Apr-04
Document File: 3 page(s) / 39K

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The Prior Art Database

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Invention Disclosure

Title: Integrated Brake

Page 02 of 3

This idea is in the field of variable speed drives and relates, in particular, to variable speed drives having active front end (AFE) functionality (AFE drives). mode. In the normal mode, a load (typically a motor) is driven by an IGBT module that draws power from a DC link. In the braking mode, power is provided (typically from a motor/generator)

Some known AFE drives have a dedicated brake chopper for braking operation which leads to

additional part count, cost and potentially reduced reliability. This idea seeks to provide brake

chopper functionality in an alternative manner.

There are two modes of operation of an existing AFE drive: a "normal" mode and a "braking"

and tends to result in the DC link voltage rising. As is known in the art, the braking mode may

use a chopper circuit to dissipate energy to prevent the DC link voltage from rising too high.

The circuit schematic below shows an exemplary implementation of the present idea. The

circuit schematic above shows an active front end (AFE) system including an AC supply, an

LCL filter and an active infeed converter (AIC). The AIC is a controllable rectifier and is used to

generate the required DC link voltage. The specific configuration of the circuit below is an

example - many variants are possible.

In the normal mode of operation of the circuit above, the contactor CON1 is closed and the

contactor CON2 is open, such that the resistors R1, R2 and R3 are disconnected. Thus, the

AFE stage works as in existing AFE systems with the AIC circuit (consisting of IGBTs 1 to 6)

providing a DC lin...