High-Bandwidth Phase Current and DC-Link Voltage Sensing Reference Design for Three-Phase Inverters

1 января 2018

The TIDA-01541 reference design reduces system cost and enables a compact design for isolated phase current and DC link voltage measurement in three-phase inverters, while achieving high bandwidth and sensing accuracy. The output of the isolated amplifiers is interfaced to the internal ADC of the MCU using a differential-to-single-ended circuit. Use of isolated amplifiers enables using SAR ADC within MCU, thereby lowering system cost without any trade-offs on the current sensing. The 8-pin package reduces board form factor. High bandwidth of the isolated amplifier enables protection of IGBTs within 3.5 µs and high-performance specifications enable high-accuracy current and voltage measurements. The DC link voltage measurement is done with a high input impedance to avoid effect of source impedance due to high-voltage potential divider to improve accuracy.

Особенности

Reinforced, isolated inverter suited for 400-V to 1200-V DC-link drives rated up to 10 kW Reinforced, isolated amplifiers with high bandwidth (> 200 kHz) enable low latency current sensing and fast overcurrent detection (< 3 µs) to protect power stage Reinforced, isolated amplifier with high impedance input optimized for precision sensing of high-impedance nodes like DC-link voltage, ±1% error for DC-link voltage sensing accuracy from 0-V to 1026-V DC Calibrated current measurement error of ±0.5% over ±50-A FSR and across temperature range from –25°C to +85°C Reinforced, isolated amplifier with low power consumption allows powering from gate drivers bootstrap capacitor simple LDO Protection against DC bus undervoltage, overvoltage, overload, ground fault, and overtemperature