This paper presents a new method for calculating the braking force of a drum-type eddy current brake with a two-layer structure. The drum-type eddy current brake should have a structure that improves the braking force by applying a material with high conductivity inside the drum because the eddy current loss generated from the drum is used as the braking force. In addition, because the eddy current brake operates at various speeds while braking the vehicle, it is necessary to grasp the braking force according to the speed. Furthermore, because the material of the drum is composed of non-laminated iron having conductivity, the skin effect and the armature reaction phenomenon appear, and the skin depth and the air-gap flux density are different depending on the braking speed. In this paper, the value of the eddy current loss of the eddy current brake with a copper coating inside the drum is newly presented and compared with the finite-element analysis results. In addition, the change in the speed-torque curve according to the conductivity value of the drum and inner coating material are shown. Finally, an experiment was conducted to compare and verify the characteristic curve of the eddy current brake obtained from the newly derived equations.

This paper proposes an algorithm to obtain better results in the integrated control by reflecting the characteristics of the individual control of the front wheel and the rear wheel of tram systems. In the case of the surface transportation, which has recently been introduced, severely curved driving performance is required for the downtown. It is possible to decrease the curve radius and to improve the performance of the straight driving with the individual torque control. Therefore, the individual torque control performance of the motor is the most important point of the surface transportation. The front and rear wheels have different torque characteristics, and the length of the bogie during curve travel also affects these results. This system is more controllable than the system with 1Controller 4Motor (1C4M) in the form of 2C4M with the front and rear wheels being individually controlled, allowing more precise control because of its higher degree of freedom. Because of this individually controlled characteristic, it is possible to control more precisely in the integrated control considering the characteristics of the front wheel and the characteristics of the rear wheel. The validity of the proposed control algorithm is verified by experimental results using a small-scale bogie system.

This study presents the characteristics and performance of a motor at the operating point based on pulse-width modulation (PWM). PWM is used in modulating the output voltage of a three-phase inverter. The PWM technique has advantages and disadvantages depending on the system size and operating range. For example, some discontinuous pulse-width modulation (DPWM) techniques are advantageous in low-cost systems because they can reduce the number of switches. Some PWM techniques are complicated for software construction and require a lot of computation. In this paper, PWM techniques were constructed by using the offset voltage injection method. Therefore, the construction of the PWM technique is simplified by the method. In an experimental setup, an interior permanent-magnet synchronous motor (IPMSM) and a three-phase inverter were implemented to test motor control performance depending on the PWM technique. In addition, the current control characteristics and inverter efficiency were analyzed and compared depending on the speed and load of the motor. According to the results of this paper, it is possible to compare the motor and inverter control characteristics using various types of PWM rapidly. Additionally, it will help to select an appropriate PWM technique for a specific system.

Independently rotating wheelsets (IRWs) with individually driven wheel motors enable compact low‐floor rail bogies and improved curving, but their running behaviour depends on how accurately traction and differential wheel torques are realised under electrical constraints. This paper presents a constraint‐aware wheel‐torque realisation and allocation framework for IRW bogies using surface‐mounted PMSM traction drives. An integrated control‐oriented model couples linearised lateral–yaw bogie dynamics with a simplified PMSM torque‐response model under field‐oriented control. Feasible current references over constant‐torque and field‐weakening regions are generated using a flux‐map‐based reference generator that maps demanded torque to ‐ and ‐axis current commands whilst accounting for current limits and DC‐link voltage variations. A multi‐input control architecture is adopted: a speed PI loop determines traction demand, an LQ‐servo loop determines yaw‐moment demand and a scaling‐based allocator distributes the demands to four wheel motors with saturation handling. Simulations show simultaneous speed tracking and lateral displacement regulation on straight and curved tracks whilst mitigating hunting‐like oscillations. Experiments on a 1/5‐scale IRW test rig validate stable lateral guidance and torque tracking, with drive currents and voltage utilisation kept within prescribed limits.

Independently rotating wheelsets (IRWs) are increasingly adopted in low-floor urban rail vehicles because they enable compact bogie layouts and improved curving performance. However, their limited natural self-centering capability can lead to lateral offset from the track centerline, increased flange contact, and degraded lateral guidance performance. This paper presents an LQ-servo-based differential-torque control method for active centering of IRWs using a control-oriented state-space model derived from linearized wheel–rail creep-force relations. Rather than proposing a new control algorithm, this study establishes and experimentally validates an integrated modeling–control–validation framework for differential-torque active centering, providing new quantitative evidence of its effectiveness. The left and right wheel torques are employed as actuation inputs to regulate the lateral displacement of the wheelset, while a conventional proportional–integral–derivative (PID) controller is implemented as a baseline for comparison. The two controllers are evaluated through numerical simulations and validated experimentally using a 1/5-scale IRW roller rig. Compared with the PID controller, the LQ-servo controller achieves faster centering, improved yaw damping, and reduced steady-state lateral offset. In particular, under representative parameter variations, the fixed-gain PID controller loses stability, whereas the LQ-servo controller remains stable and maintains accurate centering, indicating lower sensitivity to the considered parameter variations in the simulation study, while the hardware experiments confirmed real-time implementation in the presence of unmodeled physical effects. These findings support the effectiveness of the proposed modeling and control approach for active centering of independently rotating wheelsets.