Power Factor Improvement of a Linear Vernier Permanent-Magnet Machine Using Auxiliary DC Field Excitation

Permanent magnet vernier machines (PMVMs) gained a lot of interest over the past couple of decades. This is mainly due to their high torque density enabled by the magnetic gearing effect. This study will provide a thorough review of recent advances in PMVMs. This review will cover the principle of operation and nature of magnetic gearing in PMVMs, and a better understanding of novel PMVM topologies using different winding configuration as well as different modulation poles and rotor structures. Detailed discussions on the choice of gear ratio, slot-pole combinations, design optimisation and role of advanced materials in PMVMs will be presented. This will provide an update on the current state-of-the art as well as future areas of research. Furthermore, the power factor issue, fault tolerance as well as cost reduction will be discussed highlighting the gap between the current state-of-the art and what is needed in practical applications.

Section: Flux Modulation Poles (Fmps)mentioning

confidence: 99%

Permanent magnet vernier machine: a review

El-Refaie

2019

“…Recently, there are some investigations on a new type of linear primary PM vernier (LPPMV) machines, thanks to its mechanical integrity, high-thrust, low-speed, and low cogging torque characteristics [16,17]. Regarding the mentioned WEC type, there are some research on the linear vernier machines (LVMs) as the WEC, where the PM is commonly used in their structure, as well as the various structures are proposed [16,[18][19][20][21][22][23][24][25][26][27]. LVMs modelling is an important issue, which has been investigated by researchers.…”

Section: Introductionmentioning

confidence: 99%

Linear vernier machine wave converter modelling and analysis by MEC

Naderi

Sharouni

Moradzadeh

2020

This study presents a novel technique for modelling of linear primary permanent-magnet (PM) vernier machine wave converter based on an improved magnetic-equivalent-circuit (MEC) method. Saturation effect is considered by a new method, where the B-H curve fitting is performed using a novel non-linear function. The machine properties such as the number of PMs, number of slots, magnets size, and all other machine parameters can be selected arbitrarily in the proposed model. The machine structure is considered by 12 individual zones. Each of the flux tubes in core and air gaps is modelled by a non-linear reluctance, and the machine performances in both transient and steady-state conditions are studied. Various machine properties such as magnets size and winding configuration are analysed and the dynamic behaviour is compared in various cases. Comparison to finite-element method (FEM) shows the effectiveness and accuracy of the proposed MEC method and its much shorter processing time compared with FEM.

“…Linear electrical machines can offer direct linear motion without any rotation to translation conversion equipment, resulting in higher efficiency and better dynamic performance. They are widely applied in industrial and military applications [1, 2]. Compared with conventional linear motors, the Halbach array‐linear vernier permanent magnet machine (H‐LVPMM) has the feature of high force density and low force ripple.…”

Section: Introductionmentioning

confidence: 99%

Thrust force ripple reduction of H‐LVPMM based on dynamic harmonic current compensation

Chen

Kong

Zhou

et al. 2020

Through the structural optimisation, the Halbach array‐linear vernier permanent magnet machine (H‐LVPMM) offers a higher force with extremely low ripple. However, thrust force ripple is minimised rather than eliminated and it reduces the precision of the control system. The thrust force ripple includes cogging force, end force and electromagnetic thrust ripple. Since the structural optimisation makes three phases balanced, the electromagnetic thrust ripple can be ignored. Here, a disturbance observer is proposed to observe and compensate the thrust force ripple by injecting the correspondent harmonic current into the closed‐loop controller in a feedforward method. It leads to second, fourth and sixth harmonic components in the q‐axis current. The closed‐loop current control with vector proportional and integral (VPI) regulator is applied to guarantee the current tracking accuracy of the harmonic components. Parameters are optimised according to the thrust force ripple harmonics and the open‐loop Bode diagram. The impact of thrust ripple is eliminated by the proposed control method. Experimental results show the validity of the disturbance observer and the VPI current controller.