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1 – 10 of 37Abdelouahab Zaatri, Norelhouda Azzizi and Fouad Rahmani
This paper initially presents the results of the analysis of a non linear on/off control system which is capable of generating a pulse width modulation (PWM). This technique can…
Abstract
This paper initially presents the results of the analysis of a non linear on/off control system which is capable of generating a pulse width modulation (PWM). This technique can be used to design PWM choppers that can be dedicated to regulate fluctuating power supplies (photovoltaic, wind turbines, etc.). However, since the PWM losses mainly depend on the switching frequency, thus, the determination of an optimal frequency is required. Indeed, on the one hand, we seek to operate at high frequencies to reduce the residual noise by filtering. On the other hand, there is a limitation of the switching frequency due to the physical switching elements properties. Therefore, a compromise has to be made in order to determine an optimal switching frequency that minimizes the switching power losses. The main objective of this work is to present a technique that enables to sizing the chopper parameters based on the minimizing of the switching losses. An illustrative example of the proposed technique for sizing a PWM chopper is presented.
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Abdelouahab Zaatri, Norelhouda Azzizi and Fouad Rahmani
This paper initially presents the results of the analysis of a non linear on/off control system which is capable of generating a pulse width modulation (PWM). This technique can…
Abstract
This paper initially presents the results of the analysis of a non linear on/off control system which is capable of generating a pulse width modulation (PWM). This technique can be used to design PWM choppers that can be dedicated to regulate fluctuating power supplies (photovoltaic, wind turbines, etc.). However, since the PWM losses mainly depend on the switching frequency, thus, the determination of an optimal frequency is required. Indeed, on the one hand, we seek to operate at high frequencies to reduce the residual noise by filtering. On the other hand, there is a limitation of the switching frequency due to the physical switching elements properties. Therefore, a compromise has to be made in order to determine an optimal switching frequency that minimizes the switching power losses. The main objective of this work is to present a technique that enables to sizing the chopper parameters based on the minimizing of the switching losses. An illustrative example of the proposed technique for sizing a PWM chopper is presented.
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Igor Y. Korotyeyev and Zbigniew Fedyczak
Focuses on steady state modelling of basic unipolar non‐isolated PWM AC line matrix‐reactance choppers (MRC). Their single‐phase topologies are similar to well‐known basic DC/DC…
Abstract
Purpose
Focuses on steady state modelling of basic unipolar non‐isolated PWM AC line matrix‐reactance choppers (MRC). Their single‐phase topologies are similar to well‐known basic DC/DC converter ones. The MRC are built up through the adaptation of DC/DC converter topologies, which are based on the substitution of self‐commutated unidirectional switches by bi‐directional ones.
Design/methodology/approach
Presents an approach to modelling of the MRC with averaging operator different to the one used in averaged modelling of the DC/DC converters. There is running averaging of each switching period in the proposed approach. Following this, there is a demonstration of the solutions convergence of the state space and averaged state space equations for infinitive switching frequency.
Findings
The running averaging of each switching period should be used if averaged state space method is applied to the analysis of presented choppers. A circuit averaged model build‐up procedure of the presented choppers is the same as for the DC/DC ones.
Originality/value
Presents a quantitative assessment of accuracy for the averaged models of the presented MRC for finite switching frequency.
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Igor Ye. Korotyeyev and Zbigniew Fedyczak
The purpose of this paper is to introduce methods for calculating steady‐state and transient processes in a symmetrical three‐phase matrix‐reactance frequency converter (MRFC)…
Abstract
Purpose
The purpose of this paper is to introduce methods for calculating steady‐state and transient processes in a symmetrical three‐phase matrix‐reactance frequency converter (MRFC). The MRFC in question makes it possible to obtain a load output voltage much greater than the input voltage.
Design/methodology/approach
MRFCs based on a matrix‐reactance chopper are used for both frequency and voltage transformation. The processes in a MRFC system are described by nonstationary differential equations. A two‐frequency complex function method is proposed for solving non‐stationary equations in steady‐state. The method is applied to a state‐space averaged mathematical model used in the analysis of the discussed MRFC. A two‐frequency matrix transform is proposed for solving non‐stationary equations. This method can be used to find both transient and steady‐state processes.
Findings
The two‐frequency complex function method permits the reduction from 12 non‐stationary differential equations to four stationary differential equations. The two‐frequency matrix transform allows the transformation of non‐stationary differential equations to stationary ones. By using these methods descriptions of steady‐state and transient properties of buck‐boost MRFCs are obtained.
Originality/value
A new method of solving of nonstationary differential equations is presented. The method is useful for process analyses in nonstationary power electronic converters.
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Zbigniew Fedyczak, Leszek Frąckowiak and Maciej Jankowski
Aims to focus on steady state and transient state analysis of basic properties of new solution for a single‐phase serial AC voltage controller. Furthermore, simulation and…
Abstract
Purpose
Aims to focus on steady state and transient state analysis of basic properties of new solution for a single‐phase serial AC voltage controller. Furthermore, simulation and experimental test results of 3 kVA models are provided to confirm and verify the theoretical approach.
Design/methodology/approach
Presents a converter with auxiliary transformer and bipolar PWM AC matrix‐reactance chopper (MRC), based on Ćuk B2 topology. The MRC has the possibility of bipolar AC voltage conversion with magnitude of voltage transformation function greater than 1. The peak voltage detection method in the control circuit is applied to fast control of the load voltage changes. The steady state and transient state theoretical analysis based on averaged models of the presented controller is used. There is a four‐terminal description of the basic properties in the presented approach.
Findings
In the proposed solution only half the number of switches compared with the case of full bridge matrix chopper solution is used. The nominal load voltage can be obtained even for 50 per cent step‐down of the supply voltage.
Originality/value
Presents new topology and properties of single‐phase serial AC voltage controller.
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Abdelouahab Zaatri and Souad Belhour
This paper presents the analysis of a nonlinear on/off control system including a filter of a second order in the closed loop. The proposed system is capable of generating a pulse…
Abstract
This paper presents the analysis of a nonlinear on/off control system including a filter of a second order in the closed loop. The proposed system is capable of generating a pulse width modulation which is used to design and built up a PWM (Pulse Width Modulation) chopper dedicated to regulate fluctuating power supplies such as photovoltaic, wind turbine systems; etc. The use of the second order filter aims to compensate the output against the fluctuations of irradiation as well as the variation of the load. The study essentially focuses on determining the relationship between the pulse durations with respect to system parameters and technological requirements. The theoretical study is followed by a simulation of a DC-DC chopper.
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Moussa Boukhnifer, Nadir Ouddah, Toufik Azib and Ahmed Chaibet
The purpose of this paper is to propose two energy management strategies (EMS) for hybrid electric vehicle, the power system is an hybrid architecture (fuel cell (FC)/battery…
Abstract
Purpose
The purpose of this paper is to propose two energy management strategies (EMS) for hybrid electric vehicle, the power system is an hybrid architecture (fuel cell (FC)/battery) with two-converters parallel configuration.
Design/methodology/approach
First, the authors present the EMS uses a power frequency splitting to allow a natural frequency decomposition of the power loads and second the EMS uses the optimal control theory, based on the Pontryagin’s minimum principle.
Findings
Thanks to the optimal approach, the control objectives will be easily achieved: hydrogen consumption is minimized and FC health is protected.
Originality/value
The simulation results show the effectiveness of the control strategy using optimal control theory in term of improvement of the fuel consumption based on a comparison analysis between the two strategies.
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Keqiang Bai, Yunzhi Luo, Guanwu Jiang, Guoli Jiang and Li Guo
This paper aims to propose a pulsing type joint servo driver-based obstacle surmounting method for a humanoid robot according to the whole-body dynamics model, which fully takes…
Abstract
Purpose
This paper aims to propose a pulsing type joint servo driver-based obstacle surmounting method for a humanoid robot according to the whole-body dynamics model, which fully takes into account the relationship between the whole-body stability margin and instantaneous torque.
Design/methodology/approach
First, the authors designed a new practical instantaneous large torque strategy for a pulsing type joint servo driver by modeling the whole-body dynamics of the humanoid robot. The work also considered joint angle planning based on the dynamic model for crossing obstacles. Second, in the simulation and experimentation, the instantaneous torque of the driver is used to realize successful crossing of obstacles by the humanoid robot. This verifies the correctness of the whole-body dynamics model and the feasibility of the method for crossing obstacles.
Findings
The experimental data and results are described and analyzed, showing that the proposed method is feasible and effective through simulation and implementation.
Originality/value
The main contribution is the humanoid robot’s actuation control technology and humanoid action realization, which could be used for squatting and moving heavy objects to help a humanoid robot adapt effectively.
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Tapas Kumar Mohapatra and Asim Kumar Dey
This study aims to propose a unique algorithm-based hysteresis current control technique (HCCT) for induction motor using a single-phase voltage source inverter (SPVSI) to…
Abstract
Purpose
This study aims to propose a unique algorithm-based hysteresis current control technique (HCCT) for induction motor using a single-phase voltage source inverter (SPVSI) to eliminate both sub and inter harmonics (SIH) and electromagnetic interference (EMI). The total harmonic distortion (THD) of the load current also reduces in comparison to standard HCCT and modified technique-based existing HCCT.
Design/methodology/approach
Matlab simulation has been carried out to develop an SPVSI model and the unique algorithm-based HCCT. The same platform has also been used to develop a few existing HCCTs such as standard, dual-band and modified. The switching frequency and harmonic analysis of load currents for all the HCCTs have been compared in the paper. The hardware implementation of the proposed algorithm-based HCCT was also verified and compared with the simulation results.
Findings
The proposed unique algorithm-based HCCT provides the benefits of both unipolar and bipolar switching techniques. It reduces the switching frequency as unipolar switching scheme and eliminates the EMI. It also reduces THD and nullifies SIH of the load current. This enables an improvement in the overall performance and efficiency of the motor.
Practical implications
This proposed HCCT eliminates the SIH and improves the overall efficiency of the motor, hence can prevent overheating, vibration, acoustic noise, pulsating torque and braking of the rotor shaft of the motor and increasing the reliability of the system.
Social implications
It can be implemented for the motors that are used in household applications and electric vehicles through one-phase inverter.
Originality/value
This proposed HCCT has detected the zero crossing point of reference current, allowed samples and shifted the necessary amount of hysteresis band at zero crossing region to eliminate SIH and THD.
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Kirubakaran Dhandapani and Rama Reddy Sathi
The purpose of this paper is to present, a novel boost‐active clamp bridge single stage high‐frequency zero voltage soft‐switching‐pulse width modulation (ZVS‐PWM) inverter, which…
Abstract
Purpose
The purpose of this paper is to present, a novel boost‐active clamp bridge single stage high‐frequency zero voltage soft‐switching‐pulse width modulation (ZVS‐PWM) inverter, which converts the utility frequency AC power into high‐frequency AC power with an embedded controller. This single stage high‐frequency inverter is composed of a single‐phase diode bridge rectifier, a non‐smoothing filter, a boost‐active clamp bridge type ZVS‐PWM high‐frequency inverter, and an induction‐heated load with planar type litz wire working coil assembly. Also, the paper discusses how to extend the soft‐switching operation ranges and improve power conversion efficiency.
Design/methodology/approach
The proposed converter is simulated and it is implemented using embedded controller.
Findings
It was found that the single stage high‐frequency induction heating (IH) inverter using boosted voltage function can eliminate the DC and low‐frequency components of the working coil current and reduce the power dissipation of the circuit components and switching devices.
Originality/value
The paper shows that the PWM HF inverter is preferred for IH, since it has reduced switching losses and switching stresses. The paper can be extended to PC‐based wireless control, which can be part of a distributed control system in major industrial heating systems.
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