Oversampled deadbeat current control strategy for PMSM drives

This paper presents a novel deadbeat current control approach for Permanent Magnet Synchronous Motors (PMSMs) drives capable of operating at a controller sampling frequency multiple of the power converter switching frequency. The proposed technique permits to achieve a constant switching frequency and an optimal current ripple along with a high current loop bandwidth and robust behaviour to parameter variation

A fractional delay variable frequency repetitive control for torque ripple reduction in PMSMs

Based on the internal model principle, repetitive controller (RC) is capable to reduce periodic torque ripple by generating a compensating action that consequently need to be synchronized with the original ripple. However, the synchronization is difficult to achieve using the conventional RC when the sampling frequency is not integer multiple of the speed (known as fractional delay issue), or when the speed varies widely. To solve this problem, this paper presents a fractional delay variable frequency torque ripple reduction method for PMSM drives using the combination of angle-based RC and deadbeat current control (DBCC). Four aspects of innovations are included in the proposed control to improve the synchronization. The experimental results show that the proposed control can effectively reduce torque ripple even during speed and load transient

IGBT-SiC dual fed ground power unit

This paper presents the design and control of a three-phase ground power supply unit for aircraft servicing. A new mixed technology converter composed by a three-phase Silicon Carbide (SiC) full bridge unit and a three-phase full bridge IGBT unit connected across the same dc link is used instead of the conventional full bridge configuration. In order to satisfy the stringent requirements of the output voltage quality particular attention is given to the controller. The common dc link topology of the converter allows circulation of Zero Sequence Current (ZSC), therefore also a 0 axis regulator is necessary. The state space model of the system considering the LC output filter is presented and used in order to synthetize the controller parameters using the Optimal Control theory

The design of a position-based repetitive control for speed ripple reduction in PMLSMs

Periodic speed errors can occur in permanent magnet linear synchronous machines for two reasons: 1) a periodic reference signal; 2) cogging force and friction. For reducing such periodic errors, iterative learning control or repetitive control approaches, used in conjunction with more common control actions, can be strongly effective. However, the design of the stability filter, robustness filter and other parameters for a traditional repetitive controller can be a complex task and may need to be adjusted when the frequency of such periodic error varies. Existing solutions tend to develop more adaptive tuning methods for repetitive controller to enhance the whole control system. This paper shows that the performance of a traditional speed loop can be enhanced with a repetitive controller without complicating the tuning of the repetitive controller. Consequently, a position-based repetitive control combined with deadbeat current control method is proposed. Simulation results show that the proposed method is effective for reducing speed ripple at difference frequencies without necessarily adjusting its parameters

Speed Finite Control Set Model Predictive Control of a PMSM fed by Matrix Converter

This paper presents a new speed Finite Control Set Model Predictive Control (FCS-MPC) algorithm which has been applied to a Permanent Magnet Synchronous Motor (PMSM) driven by a Matrix Converter (MC). This method replaces the classical cascaded control scheme with a single control law that controls the motor currents and speed. Additionally, unlike classical MC modulation methods, the method allows direct control of the MC input currents. The performance of the proposed work has been verified by simulation studies and experimental results

Sensorless finite-control set model predictive control for IPMSM drives

This paper investigates the feasibility of a sensorless field oriented control (FOC) combined with a finite control set model predictive current control (FCS-MPC) for an interior permanent magnet synchronous motor (IPMSM). The use of a FCS-MPC makes the implementation of most of the existing sensorless techniques difficult due to the lack of a modulator. The proposed sensorless algorithm exploits the saliency of the motor and the intrinsic higher current ripple of the FCS-MPC to extract position and speed information using a model-based approach. This method does not require the injection of additional voltage vectors or the periodic interruption of the control algorithm and consequently it has no impact on the performance of the current control. The proposed algorithm has been tested in simulation and validated on an experimental set-up, showing promising results

Position control study of a bearingless multi-sector permanent magnet machine

Bearingless motors combine in the same structure the characteristics of conventional motors and magnetic bearings. Traditional bearingless machines rely on two independent sets of winding for suspension force and torque production, respectively. The proposed Multi-Sector Permanent Magnet (MSPM) motor exploits the spatial distribution of the multi-three-phase windings within the stator circumference in order to produce a controllable suspension force. Therefore, force and torque generation are embedded in the same winding setting. In this paper the force and torque generation principles are investigated and a mathematical model is presented considering the rotor displacement. A two Degree of freedom (DOF) position controller is designed taking into consideration the rotor overall dynamic system and a controller gains selection strategy is suggested. A simulation study of the bearingless system in different operating conditions is presented and the suspension force and torque produced are validated through Finite Element Analysis (FEA)

Radial force control of multi-sector permanent magnet machines for vibration suppression

Radial force control in electrical machines has been widely investigated for a variety of bearingless machines, as well as for the conventional structures featuring mechanical bearings. This paper takes advantage of the spatial distribution of the winding sets within the stator structure in a multisector permanent-magnet (MSPM) machine toward achieving a controllable radial force. An alternative force control technique for MSPM machines is presented. The mathematical model of the machine and the theoretical investigation of the force production principle are provided. A novel force control methodology based on the minimization of the copper losses is described and adopted to calculate the d–q axis current references. The predicted performances of the considered machine are benchmarked against finite-element analysis. The experimental validation of the proposed control strategy is presented, focusing on the suppression of selected vibration frequencies for different rotational speeds

Radial force control of multi-sector permanent magnet machines

The paper presents an alternative radial force control technique for a Multi-Sector Permanent Magnet machine (MSPM). Radial force control has been widely investigated for a variety of bearingless machines and can be also applied to conventional PMSM aiming the reduction of the mechanical stress on the bearings as well as reduce the overall vibration. Traditional bearingless motors rely on two independent sets of windings dedicated to torque and suspension respectively. The work presented in this paper takes advantage of the spatial distribution of the winding sets within the stator structure towards achieving a controllable net radial force. In this paper the α-β axis model for the MSPM and the theoretical investigation of the force production principle is presented. A novel force control methodology based on the Single Value Decomposition (SVD) technique is described. The predicted performances of the MSPM have been validated using Finite Element simulations and benchmarked against state of the art control techniques

Design of a repetitive controller as a feed-forward disturbance observer

From the structure point of view, a repetitive controller (RC) is considerably similar to a disturbance observer. By adding a correction term to the traditional RC and considering the disturbances as states, the repetitive controller can be designed in the same way as a disturbance observer. This paper presents therefore a new simple way of tuning a repetitive controller. Simulations show that, when compared with the traditional RC, the proposed RC configuration can achieve greater stability margin. As opposed to the traditional plug-in RC, the new RC structure studied in this paper is also shown to be robust against variations in the inner loop delays if it is used in a cascaded configuration. The immunity to plant parameter variations is another added benefit of the proposed controller