Reference design uses GaN power stage for 99%-efficient 200V drive

Reference design uses GaN power stage for 99%-efficient 200V drive

Technology News |
Texas Instruments has added a reference design for a 200-V, 2-kW AC servo motor drive, that uses a three-phase, gallium nitride (GaN) power module-based inverter configuration, and delivers, TI says, faster, more precise motor control.
By Graham Prophet


The Three-Phase High-Frequency GaN Inverter Reference Design features TI’s LMG3410 600-V, 12-A GaN power module with an integrated FET, gate driver and protection, announced in 2016. The GaN module allows the design to switch up to 5x faster than silicon FETs, while achieving efficiency levels greater than 98% at 100 kHz and greater than 99% at 24 kHz pulse width modulation (PWM) frequency. Operating the inverter at 100 kHz significantly helps improve torque ripple when used with low-inductance motors.


The GaN inverter power stage interfaces with microcontrollers (MCU), including TI’s TMS320F28379D drive control system-on-chip to help dynamically adjust voltage frequency and achieve ultra-fast current loop control. See also Fast, sub-1-µsec, MCU control loop code can cut an FPGA from architecture.


In addition to the GaN module, the reference design relies on TI’s AMC1306 isolated delta-sigma modulators with current sensing to increase motor control performance. TI’s ISO7831 digital isolator also provides reinforced isolation between the MCU and the design’s six PWMs.


The three-phase inverter design features fast switching transition of less than 25 nsec, without any switch node voltage ringing, reducing EMI. The 600-V and 12-A LMG3410 GaN FET power stage allows for fast and easy PCB layout and small form-factor design.


The image shows how the reference design might appear when built, this board is not available as a product.





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