34 research outputs found
A switched reluctance motor torque ripple reduction strategy with deadbeat current control and active thermal management
This paper presents a switched reluctance motor
(SRM) torque ripple reduction strategy with deadbeat current
control and active thermal management. In this method, the
SRM torque is indirectly controlled by the phase current. A
deadbeat current control method is used to improve the SRM
phase current control accuracy, so that SRM torque control
error can be reduced significantly. According to the online
measurement of the power switching device temperature, the
switching frequency will be reduced to prevent the SRM power
converter from being damaged by over-temperature. The
feasibility and effectiveness of the proposed strategy have been
verified in both simulation and experimental studies
Intelligent Control of Switched Reluctance Motor Using Fuzzy Logic and SMC Controller for EV Applications
Switched Reluctance Motors have expanded their field of application in recent years, from a control system stepping motor to high torque e-vehicle applications. High-speed operation and a light-weight driving motor are critical elements for an effective electric vehicle design. SRM's low torque-to-weight ratio and magnetless rotor design make it ideal for use in electric vehicles with less weight and low cost. The only limitation with switched reluctance motors is torque ripple and vibrations. There have been a variety of techniques to reducing torque pulsations in the SRM, by which vibration and noise can be reduced. In this paper, an optimization technique is used in switching controllers in and a comparison is done between a sliding mode controller (SMC) with a modified reaching law and by using Fuzzy Logic Controller (FLC). By using matlab Simulink the magnitude of torque ripple is simulated and compared for 8/6 pole SRM. The results shows that the torque ripple is reduced in fuzzy compared to SMC significantly
Advances in Rotating Electric Machines
It is difficult to imagine a modern society without rotating electric machines. Their use has been increasing not only in the traditional fields of application but also in more contemporary fields, including renewable energy conversion systems, electric aircraft, aerospace, electric vehicles, unmanned propulsion systems, robotics, etc. This has contributed to advances in the materials, design methodologies, modeling tools, and manufacturing processes of current electric machines, which are characterized by high compactness, low weight, high power density, high torque density, and high reliability. On the other hand, the growing use of electric machines and drives in more critical applications has pushed forward the research in the area of condition monitoring and fault tolerance, leading to the development of more reliable diagnostic techniques and more fault-tolerant machines. This book presents and disseminates the most recent advances related to the theory, design, modeling, application, control, and condition monitoring of all types of rotating electric machines
Fuzzy Controller Based DTC of SRM Drive Fed by Common High Side Asymmetric Switch Converter
The switched reluctance motor (SRM) is recently gaining huge popularity in electric vehicle (EV) applications due to its control flexibility, simple structure, lower cost and high efficiency than the synchronous and induction motors. Among all the controllers, the direct torque control (DTC) is the most preferred due to its higher efficiency, lower losses and superior control characteristics. In this paper, a 6/4 pole SRM with fuzzy logic based DTC has been proposed for the EV application along with a converter with reduced switch counts to reduce the torque ripples and enhance the performance of the system under steady and transient state conditions. The proposed system is tested and validated under various scenarios that include load torque and speed variations and compared with the vector control method. From, the investigation it has been found that the proposed technique reduces ripples from the system during all the scenarios with a resultant flux of less than 0.5pu
Model predictive current control of switched reluctance motor with inductance auto-calibration
The thesis is composed of three papers, which investigate the application of Model Predictive Controller (MPC) for current control of Switched Reluctance Motor (SRM). Since the conventional hysteresis current control method is not suitable for high power SRM drive system with low inductance and limited switching frequency, MPC is a promising alternative approach for this application. The proposed MPC can cope with the measurement noise as well as uncertainties within the machine inductance profile. In the first paper, a MPC current control method for Double-Stator Switched Reluctance Motor (DSSRM) drives is presented. A direct adaptive estimator is incorporated to follow the inductance variations in a DSSRM. In the second paper, the Linear Quadratic (LQ) form and dynamic programming recursion for MPC are analyzed, afterwards the unconstrained MPC solution for stochastic SRM model is derived. The Kalman filter is employed to reduce the variance of measurement noises. Based on Recursive Linear-Square (RLS) estimation, the inductance profile is calibrated dynamically. In the third paper, a simplified recursive MPC current control algorithm for SRM is applied for embedded implementation. A novel auto-calibration method for inductance surface estimation is developed to improve current control performance of SRM drive in statistic terms. --Abstract, page iv
A new torque ripple minimization approach for switched reluctance drives
This paper presents a new torque control function for torque ripple reduction in switched reluctance drives. The approach is based on the maximum utilization of available dc link voltage, extending the zero torque-ripple speed range. The approach is suitable for switched reluctance machines with any number of phases and stator/rotor poles. Soft switching control is deployed, which reduces switching losses. At any instant, only one phase current is controlled, significantly reducing the control complexity. Simulations are carried out on a four-phase 8/6, 4kW SRM in MATLAB/Simulink
Study of torque pulsation control of switched reluctance motor by auto-disturbance rejection control
The switched reluctance motor drives the rotor based on the principle of minimum reluctance, which is structurally simpler, but the doubly salient structure of the stator and rotor leads to severe torque pulsation. This paper briefly introduces the switched reluctance motor and the auto-disturbance rejection controller for suppressing the torque pulsation of the switched reluctance motor. Then, the auto-disturbance rejection controller was simulated in the MATLAB software, and it was compared with the direct torque control strategy. The results showed that the switched reluctance motor installed with the self-reluctance controller reached the set rotational speed faster, with a smoother torque change; when the set speed changed abruptly, it was adjusted to the new rotational speed faster, with a smooth and stable torque change; when the load torque changed abruptly, it was adjusted to the new torque smoother and faster, and the adjustment to the rotational speed was also faster
Power quality improvement utilizing photovoltaic generation connected to a weak grid
Microgrid research and development in the past
decades have been one of the most popular topics. Similarly, the
photovoltaic generation has been surging among renewable
generation in the past few years, thanks to the availability,
affordability, technology maturity of the PV panels and the PV
inverter in the general market. Unfortunately, quite often, the PV
installations are connected to weak grids and may have been
considered as the culprit of poor power quality affecting other
loads in particular sensitive loads connected to the same point of
common coupling (PCC). This paper is intended to demystify the
renewable generation, and turns the negative perception into
positive revelation of the superiority of PV generation to the power
quality improvement in a microgrid system. The main objective of
this work is to develop a control method for the PV inverter so that
the power quality at the PCC will be improved under various
disturbances. The method is to control the reactive current based
on utilizing the grid current to counteract the negative impact of
the disturbances. The proposed control method is verified in PSIM
platform. Promising results have been obtaine
Real-time model-based loss minimisation control for electric vehicle drives
PhD ThesisEnvironmental concern and the opportunity for commercial gain are two
factors driving the expansion of the electric vehicle (EV) market. Due to
the limitations of current battery technology, the efficiency of the traction
drive, which includes the electric motor and power electronic converter,
is of prime importance. Whilst electric machines utilising permanent
magnets (PMs) are popular due to their high energy density, industry
concerns about the security of supply have led to interest in magnet-free
solutions. Induction machines (IMs) offer such an option.
Control of IMs is a mature but complex field. Many techniques for optimising
the efficiency of the drive system have been proposed. The vast
majority of these methods involve an analytical study of the system to
reveal relationships between the controlled variable and efficiency, allowing
the latter to be optimised. This inevitably involves simplifications
of the problem to arrive at a practically-implementable control scheme.
What has not been investigated is real-time calculation of the system
losses in order to optimise the efficiency, and the work presented in this
thesis attempts to achieve this.
The conventional control scheme is examined and a new structure implemented
where a model of the system loss is able to directly influence
the switching action of the inverter, thus reducing loss. The need to
maintain performance alongside loss minimisation is recognised and a
cost function-based solution proposed. The validation of this structure
is performed both in simulation and on a practical test platform.
A model of the principle losses in the drive system is derived, taking
into account the processing power typically available for this application,
and implemented in the structure outlined. The effect of the new
control scheme on efficiency is investigated and results show gains of up
to 3%-points are achievable under certain conditions