Simulation of Field Oriented Control in Induction Motor Drive System

Abstract--

In this paper, a 3-phase induction motor model for simulation the field oriented control (FOC) system based on space vector pulse width modulation (SVPWM) is established in Ansoft/Simplorer software. The theory of field oriented control (FOC) and the principle of space vector pulse width modulation (SVPWM) were introduced. The simulation results are presented and analyzed. A Simulink simulation model of field oriented control system is presented as a comparison under the same conditions. The results indicated that the Simplorer model had quick response speed, small torque fluctuations and good performance both in steady and dynamic states. Furthermore, the Simplorer model can be coupled with the finite element model of the motor to achieve field-circuit coupling simulation of induction motor’s field oriented control system.

High Power Factor Operation of a Three-Phase Rectifier for an Adjustable-Speed Drive

Abstract—

This paper presents a novel approach to improve the power factor (PF) and reduce the harmonics generated by an adjustable-speed drive (ASD). A high-frequency (HF) current injection technique is used to improve the PF and harmonic performance. The HF current at the same switching frequency (33 kHz) is injected into the input of a front-end rectifier from the output of an HF inverter. The main feature of the circuit is that it does not require any additional active devices for current injection. The inverter driving the induction motor is operated using a sinusoidal pulsewidth-modulation technique. The circuit simulation and experimental prototype results are presented for 67-hp (50 kW) and 3-hp three-phase induction motors, respectively.

Single Power-Conversion AC–DC Converter With High Power Factor and High Efficiency

Abstract—

This paper proposes a single power-conversion ac–dc converter with high power factor and high efficiency. The proposed converter is derived by integrating a full-bridge diode rectifier and a series-resonant active-clamp dc–dc converter. To obtain a high power factor without a power factor correction circuit, this paper proposes a novel control algorithm. The proposed converter provides single power-conversion by using the novel control algorithm for both power factor correction and output control. Also, the active-clamp circuit clamps the surge voltage of switches and recycles the energy stored in the leakage inductance of the transformer. Moreover, it provides zero-voltage turn-on switching of the switches. Also, a series-resonant circuit of the output-voltage doubler removes the reverse-recovery problem of the output diodes. The proposed converter provides maximum power factor 0.995 and maximum efficiency of 95.1% at the full load. The operation principle of the converter is analyzed and verified. Experimental results for a 400 W ac–dc converter at a constant switching frequency of 50 kHz are obtained to show the performance of the proposed converter.

DSTATCOM with Reduced Switches Using Two-Leg VSC and a Zig-Zag Transformer for Power Quality Improvement in Three-Phase Four-Wire Distribution System

Abstract-

In this paper, a new topology of DSTATCOM (Distribution Static Compensator) is proposed consisting of a two-leg VSC (voltage source converter) and a zig-zag transformer for power quality improvement in three-phase four-wire distribution systems. The DSTATCOM along with a zig-zag transformer is employed for the compensation of reactive power for the voltage regulation or power factor correction along with elimination of harmonic currents, load balancing and neutral current compensation at the point of common coupling (PCC). The performance of the proposed DSTATCOM system is validated through simulations using MATLAB software with its Simulink and Power System Blockset (PSB) toolboxes.

MATLAB/PSB BASED MODELING AND SIMULATION OF 25 KV AC RAILWAY TRACTION SYSTEM- A PARTICULAR REFERENCE TO LOADING AND FAULT CONDITIONS

Abstract --

This paper presents the modeling and simulation of a 25 kV 50 Hz AC traction system using Power System Block set (PSB) / SIMULINK software package. The three-phase system with substations, track section with rectifier-fed DC locomotives and a detailed traction load are included in the model. The model has been used to study the effect of loading and fault conditions in 25 kV AC traction. The relay characteristic proposed is a combination of two quadrilaterals in the X-R plane. A brief summary of the hardware set-up used to implement and test the relay characteristic using a Texas Instruments TMS320C50 digital signal processor (DSP) has also been presented.

Design and Performance of a Cost-Effective BLDC Drive for Water Pump Application

Abstract—

This paper presents a promising solution to the problem of the bad environmental impacts of the induction-motor-based water pumps. Due to the low wire-to-water efficiency of the current residential water heaters (around 30%), a high energy cost is paid by every household in North America and even worldwide. The contribution of this paper comes in twofolds. The first is the development of a mapping algorithm that relates the pressure head H and the water flow rate Q to a corresponding torque and speed under the chart of best efficiency point, which was programmed to the controller. The second is the development of a cost-effective brushless direct-current (BLDC) motor through an extensive numerical analysis technique. The proposed motor solution designs the BLDC with minimal pulsating torque by comparing two different designs. The new controller is based on a modified field-oriented control. The controller printed circuit board is of two layers to offer a cost-effective solution. The proposed pump eliminates the need of a battery for the controller as the control voltage is fed directly from the line together with the motor. The motor simulation model and the controller design procedure are presented with simulation results of two possible prototypes. An experimental prototype for a 150-W residential pump was built, and preliminary results are given to highlight the merits of the work.

A New General Topology for Cascaded Multilevel Inverters With Reduced Number of Components Based on Developed H-Bridge

Abstract—

In this paper, a new general cascaded multilevel inverter using developed H-bridges is proposed. The proposed topology requires a lesser number of dc voltage sources and power switches and consists of lower blocking voltage on switches, which results in decreased complexity and total cost of the inverter. These abilities obtained within comparing the proposed topology with the conventional topologies from aforementioned points of view. Moreover, a new algorithm to determine the magnitude of dc voltage sources is proposed. The performance and functional accuracy of the proposed topology using the new algorithm in generating all voltage levels for a 31-level inverter are confirmed by simulation and experimental results.

ISLANDING DETECTION IN DISTRIBUTED GENERATION

Abstract--

The advancement in new technology like fuel cell, wind turbine, photo voltaic and new innovation in power electronics, customer demands for better power quality and reliability are forcing the power industry to shift for distributed generations. Hence distributed generation (DG) has recently gained a lot of momentum in the power industry due to market deregulations and environmental concerns. Islanding occurs when a portion of the distribution system becomes electrically isolated from the remainder of the power system yet continues to be energized by distributed generators. An important requirement to interconnect a DG to power distributed system is the capability of the DG to detect islanding detection. Failure to trip islanded generators can lead to a number of problems to the generators and the connected loads. The current industry practice is to disconnect all distributed generators immediately after the occurrence of islands. Typically, a distributed generator should be disconnected within 100 to 300 ms after loss of main supply. To achieve such a goal, each distributed generator must be equipped with an islanding detection device, which is also called anti islanding devices like vector surge relay and ROCOF relay.

AN APPLICATION OF OBSERVER FOR POSITION SENSORLESS STEPPER MOTOR DRIVES

Abstract-- 
A control method for stepper motor drives system can be made in open-loop circumstance which mean the system control did not require any feedback input signal in order to run the system. By applying the right sequences of pulses, the stepper motor capable to operate as other motion control. However, the performance of such system cannot be achieved to high level condition and demanded a feedback signal input to compensate the error produced while running the drive system. Therefore, a physical sensor or an encoder is placed in the motor system to obtain the feedback and form a close-loop system for error compensation. Nevertheless, the prices of these instruments are expensive, bulky and also may degrade the system performance. As a result this project presents a sensorless system in stepper motor drive system as an alternative to develop a close-loop system where the input signals are taken from voltage and current of the magnetic flux of the stepper motor. 

A Novel Control Strategy of Three-phase, Four-wire UPQC for Power Quality Improvement

Abstract –

The current paper presents a novel control strategy of a three-phase, four-wire Unified
Power Quality (UPQC) to improve power quality. The UPQC is realized by the integration of series and shunt active power filters (APF) sharing a common dc bus capacitor. The realization of shunt APF is carried out using a three-phase, four-leg Voltage Source Inverter (VSI), and the series APF is realized using a three-phase, three-leg VSI. To extract the fundamental source voltages as reference signals for series APF, a zero-crossing detector and sample-and-hold circuits are used. For the control of shunt APF, a simple scheme based on the real component of fundamental load current (I CosΦ) with reduced numbers of current sensors is applied. The performance of the applied control algorithm is evaluated in terms of power-factor correction, source neutral current mitigation, load balancing, and mitigation of voltage and current harmonics in a three-phase, four-wire distribution system for different combinations of linear and non-linear loads. The reference signals and sensed signals are used in a hysteresis controller to generate switching signals for shunt and series APFs. In this proposed UPQC control scheme, the current/voltage control is applied to the fundamental supply currents/voltages instead of fast-changing APF currents/voltages, thus reducing the computational delay and the required sensors. MATLAB/Simulink-based simulations that support the functionality of the UPQC are obtained.

A Novel Reduced Switching Loss Bidirectional AC/DC Converter PWM Strategy With Feedforward Control for Grid-Tied Microgrid Systems

Abstract—

This paper presents a novel simplified pulse width modulation (PWM) strategy for the bidirectional ac/dc single-phase converter in a microgrid system. Then, the operation mechanism of the novel simplified PWM is clearly explained. The number of switchings of the proposed simplified PWM strategy is one-fourth that of the conventional unipolar PWM and bipolar PWM. Based on the novel simplified PWM strategy, a feasible feedforward control scheme is developed to achieve better rectifier mode and inverter mode performance compared with the conventional dual-loop control scheme. The proposed simplified PWM strategy with the proposed feedforward control scheme has lower total harmonic distortion than the bipolar PWM and higher efficiency than both unipolar and bipolar PWMs. Furthermore, the proposed simplified PWM operated in the inverter mode also has larger available fundamental output voltage VAB than both the unipolar and bipolar
PWMs. A prototype system is constructed and the control scheme is implemented using FPGA Spartan-3E XC3S250E. Both simulation and experimental results verify the validity of the proposed PWM strategy and control scheme.