The conversion and utilisation of renewable energy generations often require grid‐connected inverters. When applying LCL filter to remove power electronic chopping harmonics, the power quality faces two issues of resonance damping and grid voltage induced current distortion. Conventionally, two separate control algorithms are required to treat the two issues, requiring an additional current sensor, increasing control complexity and limiting performance. This study demonstrates that linear active disturbance rejection control (ADRC) is able to treat both resonance damping and grid voltage induced current distortion as overall disturbance at the same time through a single structure, while achieving higher power quality for dynamic, steady‐state, small and large parameter setup, as well as parameter variations, as validated by experimental results. In principle, the ADRC can be configured with or without knowledge of the system model. This study also reveals that it is the measurement noise tolerance that makes the two configurations different in practice. By using model information in ADRC algorithm, the required bandwidth can be reduced, offering more tolerance to measurement noise. Moreover, the ADRC controller has only two parameters to tune for ‘fast’ or ‘slow’, which makes it easy for implementation.

Dual-inverter fed open-end winding PMSM (OW-PMSM) drive topology can extend the speed range under limited DC bus voltage, but it suffers from the zero-sequence current (ZSC) problem when with common bus configuration. Predictive current control (PCC) is a potential high-performance control method for electric drive. However, the PCC algorithm for dual-inverter system may bring a huge computational burden because of more space vectors to traverse. In order to improve the steady-state current performance and suppress the ZSC, this paper proposes a dual-vector PCC (DV-PCC) method for OW-PMSM with ZSC hysteresis control. The reference voltage vector is predicted in advance according the model. A novel sector judgment method is used to judge the sector and sub-sector where the reference voltage vector is located, and determines the two candidate space vectors. Then the dwell time of the two candidate space vectors is calculated through the projection length of the reference voltage vector. Moreover, the switching states redundancy feature of dual-inverter system is employed to suppress ZSC. Since some space vectors correspond to multiple switching states of different zero-sequence voltages (ZSVs), the switching state whose ZSV polarity is opposite to the ZSC polarity is selected as the output to realize the hysteresis control of ZSC. When the ZSVs of the candidate space vectors contradict the hysteresis control demand, the zero-vector insertion method is used to guarantee the effective suppression of ZSC. The experiments are implemented in comparison with the existing dual-vector PCC method.

Conventional predictive position control (PPC) method balances the position, speed and current of permanent magnet synchronous machine with different weighting factors. However, tedious tuning work of weighting factors is needed. To simplify the tuning process, a cost function that includes the system position, and current information is constructed based on deadbeat control method. A novel method based voltage boundary is proposed to limit the current and speed simultaneously, the voltage regions corresponding to current and speed constraints are analyzed and the voltage duty cycle is further modified according to the voltage regions, the complex weighting factor turning work is avoided, the current and speed limits are easy to implement with proposed method and less position error can be achieved. Finally, the proposed method is experimentally compared with a conventional finite-control-set PPC method and a direct speed model predictive control method.

The system constraints (current, speed, and voltage limitations) are essential for the safety control of predictive position control (PPC) method. However, online solution of model predictive control with complex system constraints is still a challenge. In this article, a novel discrete-time model predictive position control (DMPPC) strategy for surface permanent magnet synchronous motor drive is proposed, the current, speed, and position are regulated simultaneously. The optimization model of the position control system considering system constraints is formulated, the current, speed, and voltage constraints are analyzed and transformed into the incremental voltage constraints. To reduce the calculation burden, a simplified method based on the geometric boundaries and cost function is proposed to solve the optimization problem, complex iterative calculations are avoided, the system constraints are well limited and less calculation time can be achieved. Finally, the proposed DMPPC method is experimentally verified and compared with a traditional iterative method and a cascade predictive position control (CPPC) method.

The commercial mature gallium nitride high electron mobility transistors (GaN HEMT) technology has drawn much attention for its great potential in industrial power electronic applications. GaN HEMT is known for low on-state resistance, high withstand voltage, and high switching frequency. This paper presents comparative experimental evaluations of GaN HEMT and conventional Si insulated gate bipolar transistors (Si IGBTs) of similar power rating. The comparative study is carried out on both the element and converter level. Firstly, on the discrete element level, the steady and dynamic characteristics of GaN HEMT are compared with Si-IGBT, including forward and reverse conducting character, and switching time. Then, the elemental switching losses are analyzed based on measured data. Finally, on a complementary buck converter level, the overall efficiency and EMI-related common-mode currents are compared. For the tested conditions, it is found that the GaN HEMT switching loss is much less than for the same power class IGBT. However, it is worth noting that special attention should be paid to reverse conduction losses in the PWM dead time (or dead band) of complementary-modulated converter legs. When migrating from IGBT to GaN, choosing a dead-time and negative gate drive voltage in conventional IGBT manner can make GaN reverse conducting losses high. It is suggested to use 0 V turn-off gate voltage and minimize the GaN dead time in order to make full use of the GaN advantages.

This paper deals with the analysis and comprehensive optimization of the torque and radial force ripples in the arc flux switching permanent magnet linear motor, which is equipped in the large scanning equipment. The torque ripple is caused by the no-load torque including cogging torque and end force. Specially, a worth noting problem of unbalanced radial forces is caused by the discontinuity of the arc stator, which is easily behaved as the rotor and load vibrations. In this paper, an analytical model based on the magnetic permeance function is established to analyze the principle of the no-load torque and radial force. Based on it, the optimization goal of force harmonics can be determined, and the feasible optimization approach can be predicted. It demonstrates the harmonic distribution of the torque is completely opposite to that of the radial force. Pure structural parameter optimization can not achieve the satisfactory results. To effectively suppress the no-load torque and radial force at the same time, a novel structure with two sets of specially arranged three-phase stator is proposed. An obvious optimization effect is verified according to the detailed FEM and experiment analysis.