Safe Phase Current Measurement for Motor Controlled Traction-Inverter Application

2024-28-0141

To be published on 12/05/2024

Event
11th SAEINDIA International Mobility Conference (SIIMC 2024)
Authors Abstract
Content
The Traction-Inverter is a key component of electric vehicles, as it connects the battery, the motor, and the vehicle control systems as automotive industry is moving towards electrification. Phase current measurement one of its functionalities ensures to achieve accurate motor control, efficient torque production and optimal performance in traction inverter application. This paper proposes method for phase current measurement of PMSM (Permanent magnet synchronous motor) with EVADC (Enhanced Versatile Analog-Digital-Converter) to measure current of three phases motor synchronously. To accomplish measurements free of current ripples, the EVADC module converts sensed data synchronously at the middle of the PWM (Pulse Width Modulation) trigger signal. Due to due to its high precision and flexibility, conversion speed, synchronization and parallel sampling, DMA (Direct Memory Access)- driven result handling, anti-aliasing filtering, system integration, arbitration and conversion sequences Infineon's Aurix EVADC is excellent choice for measuring phase currents. Since all phase currents should be sampled at PWM rate to ensure that measurements are aligned with switching events of IGBT switches, also to obtain real time information for fault protection and function control. To fulfill this requirement EVADC comprises a set of converter blocks that can be operated either independent from each other, sequentially chained for longer conversion sequences, or synchronized for parallel conversion of up to 4 channels. In compliance with ISO26262 requirements implemented redundancy check on measured phase currents serves several important purposes like error mitigation, fault detection, tolerance, calibration, safety and protection. EDSADC's (Enhanced Delta Sigma ADC) accuracy, continuous measurement, independent channels and built-in calibration gives excellent choice for phase current measurement redundancy check. Presented work adheres redundancy principles like preventing single points of failure achieved by safety metrics and confirmation measures like SPFM (Single point Fault Metrics) & LFM (Latent Fault Metrics) meets ISO26262 safety standards. Key Words: Traction inverter, DMA- driven result handling, anti-aliasing, PMSM, EVADC, Redundancy Check, ISO26262, SPMF, LFM.
Meta TagsDetails
Citation
Birari, A., "Safe Phase Current Measurement for Motor Controlled Traction-Inverter Application," SAE Technical Paper 2024-28-0141, 2024, .
Additional Details
Publisher
Published
To be published on Dec 5, 2024
Product Code
2024-28-0141
Content Type
Technical Paper
Language
English