Power switching circuitry of AC motor drives, particularly of small drives below 10 kW, is experiencing increasing levels of electronic integration. This trend is driven by the need for lowering manufacturing costs and achieving large scale production with automated assembly. For a 3-phase PWM inverter bridge, the state-of-art has changed from discrete devices to six-pack modules and now to intelligent power modules offering various extra control and protection features. The author reviews the recent progress in the electronically integrated power modules for variable-speed AC drives. Various aspects such as electronic construction, packaging, base/gate drive circuitry, protection and fault identification are discussed from the view-point of the user rather than the manufacturer of power modules. Application experience gained from using such modules in vector-controlled (field-oriented) induction motor drives is presented.
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