AC induction machines are popular due to their simplicity, reliability and direct operation from an AC line voltage. ACIMs are asynchronous machines and always have a lower mechanical rotor speed than the power line frequency.
Historically, variations to speed requests was a limitation for AC machines, but the development of frequency converters has simplified motor speed changes, and are now widely used.
ACIM fabrication begins with a three-phase winding placed in the winding slot of the stator. There are two basic types of rotor winding concepts. The first type places the rotor winding placed in the winding slot with a slip ring on the shaft, which historically was used for speed regulation and startup. The more common type consists of a rotor in a squirrel cage form.
The principle of operation for an ACIM is based on the voltage induction from the stator to the rotor. When the stator winding is fed by a three-phase supply voltage, the current flows in the winding and the stator rotating magnetic field is generated. Induced voltage in the rotor windings will create the rotor current and the rotor magnetic field. The interaction between two magnetic fields creates the mechanical torque needed to turn the rotor.
The operational rotor speed is lower than the stator magnetic field speed in order to achieve rotational torque.
Explore the MC34937, an industrial-grade 3-phase gate pre-driver for BLDC and PMSM motor control. The MC34937 can support 12V, 24V, and 36V motor control applications and easily interfaces to standard MCUs and DSPs.
|Controllers (MCU and DSC)|
|Kinetis® KV5x-240 MHz, Motor Control and Power Conversion, Ethernet, MCUs based on Arm® Cortex®-M7|
|Kinetis KV4x-168 MHz, High Performance Motor / Power Conversion MCUs based on Arm® Cortex®-M4||150 MHz Cortex-M4 core with DSP, floating point unit, eFlexPWM module with 312ps resolution and dual FlexCAN.|
|Digital Signal Controllers||100 MHz/100 MIPS, 256 KB flash, 320ps PWM, 2x12-bit ADCs.|
|MC56F823xx and MC56F827xx Digital Signal Controllers||MC56F823xx for advanced motor control; 5 mm x 5 mm package option.|
|Software and Tools|
|FreeMASTER Run-Time Debugging Tool||Real-time control and debugging tool for Digital Signal Controllers.|
|Real Time Control Embedded Software Motor Control and Power Conversion Libraries||Embedded Software and Motor Control Libraries.|
|Model-Based Design Toolbox||A comprehensive collection of tools that plug into the MATLAB®/Simulink® model-based design environment to support rapid application development with NXP® MCUs.|
|Motor Control Application Tuning (MCAT) Tool||MCAL is intended for the development of PMSM FOC applications, real time control structure parameter tuning.|
|Power Stage Driver|
|Three Phase Field Effect Transistor Pre-driver||Extended supply voltage operating range: 6.0 to 58 V. External FET gate drive capability of >1.0 A with protection.|