An nth Harmonic Current Suppression Method Based on the Impulse Current PWM Technique for a Multi-Phase Permanent Magnet Synchronous Motor Fed with a Current Source Inverter

Abstract

Among the existing harmonic current suppression methods, it is difficult and complicated to suppress any nth harmonic current accurately for multi-phase permanent magnet synchronous motors (PMSMs). To solve this problem, this paper takes a five-phase dual-rotor PMSM fed with a current source inverter (CSI) as an example, and proposes an nth harmonic current suppression method based on the impulse current PWM algorithm. Firstly, the analysis is conducted and presented for the nth harmonic current in the mth harmonic space. Then, based on the Sliding Discrete Fourier Transformation (SDFT), a low-pass filter (LPF) named SDFT-LPF is designed. Additionally, the impulse current PWM technique for the five-phase CSI is realized. In this paper, the experiments have confirmed that the SDFT-LPF has good filter performance. Compared with the SVPWM, the impulse current PWM technique has the same DC-link current utilization rate, but it is easier to implement. Moreover, the proposed harmonic current control method can accurately control any nth harmonic current without changing the PWM technique, which has significantly reduced the complexity of the harmonic current control. Additionally, the proposed scheme is easy to implement and can be directly extended to the multiple harmonic current’s control.

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

“…The remaining healthy AS-vectors are p H1,AS , p H2,AS , p H3,AS , and p H4,AS . To reconstruct the p F,AS , assuming that the modified parts of the From Equation (32), the equation can be obtained as Equation (33) shown at the bottom of this page, where φ F represents the axis angle of phase-F. Then, the result can be obtained as…”

“…Then according to Equations (33)(34)(35), the modified duties d F,H1 , d F,H2 , d F,H3 , and d F,H4 can be obtained. Therefore, the post-fault AS-vector duties under the SPOF can be expressed as The reconstruction process of the AS-vector p F,AS is illustrated in Figure 8.…”

“…4 of ref. [33] is considered as a compensation method for the capacitive filter compensation method used in current controllers, as shown in Figure 1. By using the inverse coordinate transformation matrices, the AS-vector duties can be calculated.…”

“…Furthermore, utilising the ampere-second (AS) balance, an impulse-current PWM technique was proposed in ref. [33]. The utilisation ratio of dc-link current in this PWM is equivalent to that of SVPWM, but this PWM is less complex.…”

“…Compared with ref. [33], this method achieves unified PWM modulation for both healthy and fault conditions, eliminates the need for sorting AS-vectors, and maintains the same dc-link current utilisation ratio as SVPWM. Based on this PWM strategy, a fault-tolerant control method is proposed using the AS-vector reconstruction method to deal with SPOF, adjacent DPOF, and non-adjacent DPOF.…”