This reference design realizes a 3 phase inverter subsystem for variable frequency AC inverter drives and servo drives. This design is particularly suited for drive architectures in which the microcontroller and inverter ground are non-isolated. The basic isolated gate driver UCC5320S is used for driving the high side inverter switches, and the compact, six pin UCC27531 low side gate driver is used for driving the bottom switches. The result is for reinforced isolation to move to the UART communication channel. Inverter half bridge leg current sensing is done in two phases using shunt resistors and the dual operational amplifier TLV9062. This drive architecture results in a reduced number of reinforced isolated channels and enables a cost optimized, compact solution. This design is controlled by a C2000 microcontroller.
Features
- 3 phase inverter power stage suited for 200-480 Vac powered drives with continous current rating up to 10 Arms
- Compact and cost-optimized solution due to:
- Movement of reinforced isolation from the power stage to the inter-processor communication channel resulting in reduction of number of reinforced isolated devices from 9 to 1
- Use of small low side gate drivers (SOT23 – 2.9 mm * 1.6 mm) and basic isolated high side gate drivers (SOIC8 – 4 mm * 5 mm)
- Single power supply rail powering all gate drivers through bootstrap technique
- High side gate driver with basic isolation in power stage minimizes creepage distances
- Low propagation delay (< 75 ns) of gate drivers enable decreasing dead time which improves inverter efficiency and distortions
- Robust solution due to gate drivers with enhanced immunity against miller dv/dt turn on events, negative input voltage handling and UVLO