Torque ripple suppression of permanent magnet synchronous machines by minimal harmonic current injection

Abstract

Reducing torque ripples in a permanent magnet (PM) synchronous machine (PMSM) system has been an essential requirement in some high-performance applications. To suppress the torque ripples caused by time harmonics and spatial harmonics, an approach based on injecting minimum harmonic currents is proposed here. The proposed method extracts torque ripples from speed fluctuations, and the gradient descent optimisation (GDO) is utilised to determine the injected harmonic currents which are the commands of the harmonic current regulators. Using the torque ripple minimisation and the injected harmonic current minimisation as the two objectives, the GDO not only minimises the torque ripples of the PMSM system but also guarantees that the magnitude of the injected harmonic currents is minimal. The proposed method is simple to implement in the hardware and does not require complex computation. Its effectiveness is verified by experimental results.

An Online Compensation Method of DC Drift for Three‐Phase Current Reconstruction with DC‐Link Resistance

“…According to Eq. (14), the DC offset value of 1.4474V should be 1796 in 12bit ADC system (V ref is 3.3V as 4096). Adapting the online compensation method, the DC offset sampling point was set in the middle moment of zero vector 111 shown in Fig.18(a).…”

“…For that there are dead time in PWM signals and time delay in analogy circuit, the sampling points of phase currents should be delayed a period of time ∆T d , as shown in Fig.18(b). In this paper, the dead area phase current reconstruction was avoided through PWM modification strategy [14] . The minimum sampling period limited to 5µs.…”

Control System for a Single-Phase DC-Excited Flux-Switching Machine With a Torque Ripple Reduction Scheme

“…Torque ripple reduction scheme for three-phase machines have been discussed extensively in the literatures. These schemes are generally based on the predictive control [13]- [16], and current shaping techniques [17]- [19]. Reference [20] presented the design of a unique current profile to reduce torque ripple on the basis of current shaping technique for single-phase DCFSM; however, only preliminary results are presented in this study.…”

Low Speed Sensorless Control Based on an Improved Sliding Mode Observation and the Inverter Nonlinearity Compensation for SPMSM

“…At present, the research question for sensorless control is how to accurately estimate the rotor position when the speed is low or even zero as the back EMF is almost zero and the signal-to-noise ratio is low [8], [9]. Considering the robustness and the nonlinear adaptability of the sliding model control [10], the SMO method is theoretically suitable for sensorless control at a low speed, however, the inherent chattering would affect the control performance.…”