An ampere‐second‐vector pulse width modulation technique and fault‐tolerant control for CSI11 fed five‐phase permanent magnet synchronous motor with multiple harmonic electromotive forces

Abstract

When dealing with safety‐critical applications that involve multiphase permanent magnet synchronous motors (PMSMs), the current source inverter (CSI) is a superior choice compared with the voltage source inverter. The conventional technique of pulse width modulation (PWM) presents a challenge for CSI, particularly during faults. The fault‐tolerant control of multiphase PMSMs fed by CSIs has not been well investigated, particularly in situations involving double‐phase open‐circuit faults. Furthermore, fault‐tolerant control becomes more complex when the multiphase PMSM includes harmonic back electromotive forces (EMFs). To deal with these issues, an ampere‐second (AS) vector PWM technique is developed for a five‐phase PMSM powered by CSI11. The modulation ratio of the proposed PWM is identical to that of space vector PWM. The proposed method, however, is easier to implement. A fault‐tolerant control method using AS‐vector is proposed for single‐phase, adjacent double‐phase, and non‐adjacent double‐phase open‐circuit faults. Additionally, a method is developed to suppress the torque ripple that results from harmonic back‐EMFs during fault conditions. Compared without the torque ripple suppression method, during the speed rising, the proposed method can reduce torque ripple to 16.7%, 54.5%, and 37.5%, respectively. The experiments have confirmed the effectiveness of the proposed PWM technique and fault‐tolerant control method.