AN3338 datasheet(6/72 Pages) STMICROELECTRONICS

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Inverter design concept and SLLIMM solution

AN3338

6/72

Doc ID 18441 Rev 4

Inverter design concept and SLLIMM solution

Motor drive applications, ranging from a few tens of watts to mega watts, are mainly based

on the inverter concept thanks to the fact that this solution can meet efficiency, reliability,

size, and cost constraints required in a number of markets.

As shown in Figure 1, an inverter for motor drive applications is basically composed of a

power stage, mainly based on IGBTs and freewheeling diodes; a driving stage, based on

high voltage gate drivers; a control unit, based on microcontrollers or DSPs; some optional

sensors for protections and feedback signals for controls.

The approach of this solution with discrete devices produces high manufacturing costs

associated with high reliability risks, bigger size and higher weight, a considerable number

of components and the significant stray inductances and dispersions in the board layout.

In recent years, the use of intelligent power modules has rapidly increased thanks to the

benefits of greater integration levels. The new ST SLLIMM family is able to replace more

than 30 discrete devices in a single package. Figure 2 shows a comparison between a

discrete-based inverter and the SLLIMM solution, the advantages of SLLIMM can be easily

understood and can be summarized in a significantly improved design time, reduced

manufacturing efforts, higher flexibility in a wide range of applications, and increased

reliability and quality level.

In addition, the optimized silicon chips in both control and power stages and the optimized

board layout provide maximized efficiency, reduced EMI and noise generation, higher levels

of protection, and lower propagation delay time.

Figure 1. Inverter motor drive block diagram

Gate driver

Power stage

Sensors

Bridge rectifier

Microcontroller

Feedback

Mains

AN3338 Datasheet(PDF) 6 Page - STMicroelectronics