This paper proposed a novel hybrid random pulse-width modulation (HRPWM) technique based on the modified SVPWM for three-phase voltage source inverters (VSIs) to eliminate the PWM acoustic noise. Due to PWM technique and switching losses considerations, ear-piercing high frequency noise from motor is common. The proposed HRPWM technique is able to remove the high frequency unpleasant acoustic noise more effectively than conventional RPWM with lower switching losses and shorter random frequency range. In addition, the PWM harmonics in phase voltage and phase current are reduced significantly. The HRPWM method is simple to implement and does not employ additional circuits in drive system. Finally, the effectiveness of the proposed approach has been confirmed by detailed experimental results.

In motor drive system, ear-piercing acoustic noise caused by high-frequency vibration from motor becomes unacceptable in sensitive environments, due to the application of pulsewidth modulation (PWM) and consideration of switching losses. In this paper, a novel method which associates a presented dual three-phase permanent magnet synchronous motor (PMSM) called dual-branch three-phase PMSM with carrier phase-shift technique is implemented to completely reduce odd-order PWM frequency vibration. The proposed motor has two no phase-shift three-phase windings, whose coils wind on the same teeth; it is driven by paralleled inverters with magnetically coupled inductors. With carrier phase shifting π, the odd-order carrier frequency current harmonics with the identical amplitude in two windings are opposite in phase, and therefore the produced magneto-motive-force (MMF) harmonics in the air gap offset with each other. The experimental results are provided to verify the validity of the proposed method in vibration reduction. Compared with the previous work of vibration reduction for dual three-phase PMSMs, the proposed method can achieve total elimination of odd-order PWM frequency vibration.

A novel robust deadbeat predictive direct speed control (RDP-DSC) method for permanent magnet synchronous motor is proposed to improve the speed control bandwidth and eliminate the conventional cascaded speed control structure. First, the basic DP-DSC method with one-step ahead time delay compensation is introduced briefly. Then, the control sensitivity analysis issue on the electrical and mechanical parameter mismatches, and external disturbance and inverter nonlinearity are inspirationally discussed. Further, based on the analysis above, a novel dual second-order sliding-mode disturbance observer (SOSMDO) structure is proposed for both current and speed disturbance suppression. The proposed RDP-DSC equipped with SOSMDO is presented with full control errors completely compensated. Meanwhile, the undesired chattering phenomenon caused by the switching function in the existing popular sliding-mode observers is eliminated by the proposed SOSMDO. Rich experiments are then performed, showing that the proposed method has strong enough robustness to various parameter mismatches and external disturbances while the system still holds the DSC methods’ advantages, such as high response speed and satisfying bandwidth.

This study proposes a sliding mode observer (SMO) based method for sensorless speed control of surface permanent magnet synchronous motor equipped with LC filter. To deal with side effects of pulse width modulation technique, LC filters are equipped between inverters and motors in some industrial applications. Therefore, filter input currents rather than stator currents will be measured by current sensors on the inverter board. Sensorless operation becomes complicated due to the differences between filter input and stator currents. When only inverter‐side current sensors are installed, the mathematical model of the LC filter should be considered. Hereby, the proposed SMO takes the LC filter into consideration, so additional measurement of stator currents is not necessary. Back electromotive forces of the PMSM are estimated by the SMO, and the rotor speed and position are calculated by the phase locked loop. The proposed approach features simplicity, and it is suitable for medium‐ and high‐speed ranges. Simulation and experimental results confirm the effectiveness of the proposed method.

This paper proposed a modified single-edge SVPWM (MS-SVPWM) technique by adjusting the zero vectors of saw-tooth carrier SVPWM technique for three-phase voltage source inverters (VSIs) to reduce the switching losses and increase the PWM noises frequency. Mathematical analysis and implementation of the proposed MS-SVPWM are demonstrated in detail. The differences in PWM noises reduction between MS-SVPWM and modified SVPWM (MSVPWM) technique are compared by time-varying PWM noises analysis, computer simulation and experimental results. With the same average switching frequency of conventional SVPWM, MS-SVPWM could increase the PWM harmonics frequency by 50%. Employing the same carrier frequency, MS-SVPWM could reduce average switching frequency by 33% compared with conventional SVPWM technique, and the switching losses could be reduced by more than 25% when phase angle is less than 60°. Reduction of switching losses would ease the cooling requirements and result in greater compactness of the system, especially vital concern in high-power applications and limited-space environments. The detailed experimental results confirm the effectiveness of the proposed MS-SVPWM at last.

In this article, a novel mode switching control (MSC) strategy is proposed containing a fast-response phase and a high-precision settling phase to meet the requirement of high-quality point-to-point permanent magnet synchronous motor servo systems. In the fast-response stage, an adaptive trajectory planning method is developed to program the q -axis current profile online based on the reference for the motor to reach the neighborhood of the reference position in minimum time. The chattering in the conventional time-optimal control is overcome and the idea that skipping speed and position loop with preplanned q -axis current trajectory is first attempted. After switching, the high-precision settling stage that is responsible for improving the transient performance in terms of reducing the overshoot and settling time is built with the proposed robust composite nonlinear feedback (RCNF) control law. This RCNF method cancels the overall disturbance through an extended state observer. The switching condition for the proposed MSC controller is clarified. Afterward, the whole closed-loop system's stability is strictly proved. Experiments are then conducted based on different scenarios to prove the effectiveness and robustness of the proposed MSC method.