Research and Development of An FPGA based Three-phase High-efficiency SiC Inverter for Electric Vehicles
This project is to apply FPGA and SiC devices to EV motor drive inverter. By increasing the sampling frequency through FPGA, the potential of SiC devices will be maximized for complex control strategies, such as high-frequency-injection sensorless control. Common-mode-noise reduction will be pursued as well by implementing various PWM patterns through FPGA.
FPGA Test Bench
This project will connect the evaluation board of Xilinx FPGA with a SiC inverter in CURENT and apply the common-mode reduction control method to the selected FPGA emulation board). Detailed plan includes: building the Matlab/Simulink model for several control algorithms, generating the FPGA code to the emulation board, developing the software and integrating it into existing FPGA SW, and testing the control algorithm on the SiC inverter based PMSM drive set in CURENT. Meanwhile other advanced control algorithms, including multiple-phase motor control, simultaneous multiple motor control, high-frequency harmonic injection sensorless control will be investigated, to maximize the benefits of SiC and FPGA.
How WBG Can Help
Though SiC devices in the EV drive system can easily go beyond 100kHz, the conventional microcontroller, when utilizing field-oriented control (FOC), implements code in the serial sequence, which limits the sampling frequency to ~10kHz. In some cases that require a lot of computation resources such as the sensorless motor control, one single microcontroller is not sufficient. This explains why the PWM updating rate is usually lower than the switching frequency. For instance, a 100kHz SiC inverter can only update the duty cycle every 10 switching periods, discounting merits of SiC devices. A high control-bandwidth microcontroller such as FPGA is can greatly enhance the performance of a WBG inverter, given modules inside the FPGA are in parallel instead of in series, which results in the sampling rate of the FOC the same as the switching frequency. Such combination of FPGA and SiC will yield a faster control response, much lower current THD, and potential cost reduction given FPGA is able to control multiple inverters together.
- Yang Huang
Wei Qian, Xi Zhang, Fanning Jin, Hua Bai, et al, "Using High-control-bandwidth FPGA and SiC Inverters to Enhance High-frequency Injection Sensorless Control in Interior Permanent Magnet Synchronous Machine", IEEE Access, 2018/7, vol.6, pp.42454 - 42466.