Abstract: This paper proposes a novel damping controller for subsynchronous resonance (SSR) mitigation using existing 11-kV variable frequency drive interfaced auxiliary power plant loads. The input of the proposed auxiliary damping controller is the turbine output power $(P_{t})$ . This is a standard signal that is monitored in power plant control rooms and is available locally without the need for additional measurement and/or communication infrastructure. The auxiliary damping controller (ADC) adds an auxiliary speed signal to the existing speed reference in the closed-loop motor drive control in response to any torsional range oscillations seen in $P_{t}$ , via a feedback compensator. The ADC extracts damping by exploiting SSR load interactions and is tuned using a residue-based pole placement technique. The ADC performance is evaluated for both torsional interaction and torque amplification types of SSR in the IEEE First Benchmark and IEEE 68-bus networks. The results show that the ADC is effective in providing positive damping to mitigate unstable SSR oscillations under a range of operating conditions. The proposed solution is a simple yet effective means of providing local control of SSR with minimal additional cost.

Abstract: This invention discloses a system and method to operate a doubly-fed induction generator (DFIG) as a grid-friendly virtual synchronous generator (VSG). It comprises a DFIG modeled as a virtual differential gear that links a rotor shaft driven by a prime mover, a virtual stator shaft coupled with a virtual synchronous generator G and a virtual slip shaft coupled with a virtual synchronous motor M, and a variable frequency drive that behaves as a virtual synchronous motor-generator set to regulate the speed of the virtual synchronous motor M so that the speed of the virtual stator shaft, i.e., the speed of the virtual synchronous generator G, is within a narrow band around the grid frequency even when the rotor shah: speed changes. As a result, a grid-connected DFIG can be controlled to behave like a virtual synchronous generator without using a PLL.

Abstract: Liquefied Natural Gas peak shaving facilities utilize large horsepower motors to drive refrigeration compressors needed for the liquefaction process. Utilities impose strict voltage flicker requirements making evaluation of various motor starting methods imperative. The large motor starting studies must be evaluated while also factoring in equipment and controls complexity and overall project capital costs. This case study will evaluate several motor starting methods, comparing technical performance and cost considerations, identifying the best method for the project requirements and reviewing the field measurements during operation confirming acceptable performance of the installed method.

Abstract: A system including a control system is provided. The control system includes a main drive that receives power from a power source and outputs a variable frequency and a variable amplitude AC voltage. The control system also includes a controller to interface with the main drive and an electric machine. The controller receives one or more electrical signals associated with an operating condition of the electric machine from one or more sensors disposed between the electric machine and the main drive. The controller determines correction information based on the received electrical signals and based on a desired operating condition of the electric machine. The controller transmits the correction information to the main drive. The correction information corresponds to a rotor position of the electric machine or operating commands configured to implement the desired operating condition of the electric machine.

Abstract: Synchronous motors are reliable and efficient, but it is relatively difficult to start them. In some cases, a variable frequency drive is utilized. In some other, asynchronous start is achieved by virtue of induced currents in a solid rotor, or a rotor damper cage installed for this purpose. In this contribution, a method to start a synchronous machine without a damper cage is presented. The starting was achieved by inverting the polarity of the rotor field winding in a timely manner with respect to the rotating stator field. The technique was verified with experiments performed on a 200 kVA experimental test rig and also simulated on a 20 MVA machine.

Abstract: Microcontroller based sample Space Vector Modulation for two-level three-phase voltage source inverter is discussed here. The system is designed in ATmega64, which is an 8-bit low cost microcontroller. A fixed number of sample is used to produce a full wave. Here, Timer overflow interrupt is used to generate every new sample. All the calculation is done in interrupt subroutine. With simple modification, the system can be integrated to a variable frequency drive (VFD) of induction motor. Simulations are performed in Matlab/Simulink and Proteus Design Suite. Similar results are found in both simulation tools. The simulation results show that the proposed modified method results in reduction of calculation cycle numbers in interrupt routine.

Abstract: In today’s competitive market, industries are facing the growing demands-for improving process efficiencies, comply with the environmental-regulations-and to meet corporate financial objectives. The dynamic industrial manufacturing market, intelligent and low cost industrial automation systems-are required to improve their productivity and efficiency. There is a need for cost effective wireless automation system-which are secured and flexible. So in this regard the present work aims at remote monitoring and control of electrical parameters such as speed, current of Variable Frequency Drive (VFD) fed-three phase Induction Motor with Programmable -Logic Controller (PLC) and LabVIEW software. The LabVIEW Graphical User Interface (GUI) act like server communicates with the remote authorized client and can access motor parameters via Transmission Control Protocol/Internet Protocol (TCP/IP). A hardware setup and an algorithm has been developed in PLC and Arduino module for acquisition of current and speed data of three phase Induction Motor. The speed and rotational directional control of induction motor is achieved through PLC programming. Object linking and Embedding for Process Control (OPC) server is used as an-interface to communicate PLC with LabVIEW software.

Abstract: Condensate pumps provide the motive force to deliver condensate from the hotwell to the deaerator storage tanks. Advanced Power Reactor 1400 (APR1400) is comprised of three 50% capacity motor drive...

Abstract: Electrical submersible pump (ESP) systems in oil field have unique features due to the long cabling effect. The electrical system for a typical ESP installation consists of a variable frequency drive (VFD), a multi-tap step-up transformer, a downhole main cable, and an electrical submersible motor. A load filter is usually required in a VFD-ESP system. In this paper, several factors that significantly affect operating conditions of an ESP system are presented through simulation and field measurements for a practical ESP system in the field. Such analysis is beneficial to field engineers and operators to better understand impacts of equipment settings.

Abstract: A pumping system pumps material or fluid, for example, downhole to perform a stimulation operation. A pumping system may comprise multiple pumps that must be powered-up in a sequence that does not overload a power source. A variable frequency drive may be coupled to a pump via a motor and may adjust the speed of the motor to control the rate of pumping of fluid from the pump. A soft-starter may be coupled to a pump via a motor to provide a constant pumping rate of fluid from the pump. A power-up sequence may be determined that provides power to the variable frequency pump and the soft-starter to power-up the corresponding motors such that the power source is not strained or overloaded. Mixing variable frequency drive driven pumps with pumps driven by a soft-starter may provide an efficient use of available power, conserve space, allow for control over a pumping rate of fluid and reduce costs.

Abstract: The topic of research “Improvements in the efficiency of the inverter involved in microgrid” is very versatile. The microgrid is one of the most prevalent areas of present research. Role of an inverter in a microgrid is very important. Our focus on the smart consumption which is the important part of microgrid. This research paper develops an approach to improve the fundamental voltage magnitude and phase angle output based on dead time (DT) compensation method for inverters. The Industrial load is comprised of running Induction motors (IM) and generators etcetera. 90 percent of an industrial load depends on induction motors. The running induction motor (IM) gives way to the abundant amount of power losses. Additionally., the parametric values of induction motors are improved and controlled by Variable Frequency Drives (VFD). Furthermore., Fundamental Voltage Magnitude is decreased without compensation and is increased after the dead time compensation technique is used. Similarly., Phase Angle output is distorted without dead time compensation and improved after dead time compensation. The designed system model is simulated for useful graphs. These results are analyzed and compared with primitive work.

Abstract: Variable frequency drives are widely used nowadays mainly because of their efficiency and reliability characteristics. Insulated Gate Bipolar Transistor active front end converters are frequently used because they offer a number of advantages such as bidirectional power flow, filter size is small, unity power factor and reduced harmonic distortion. IGBTs have unique attributes which allow VFD to actively control the power input, making it tolerant of supply side disturbances. This paper shows a MATLAB Simulink model which analyses the performance of a VFD and its control using AFE based variable frequency drive for induction motor used for crane drives in mining operations.

Abstract: Silicon carbide (SiC) metal oxide semiconductor field effect transistor (MOSFET) power module is the next generation switching device for the medium voltage (MV) variable frequency drive (VFD). This paper investigates two problems which compromise system reliability and robustness of SiC MV VFD products. The first object is to mitigate the overvoltage transients on AC induction motors when connected through a cable of arbitrary length to a MV VFD consisting of a pulse-width modulation (PWM) inverter with SiC MOSFETs. The second topic is to develop the inverter thermal model to prevent the device failure from overheat issue. One solution is to design the smart SiC MOSFET gate driver with adjustable turn-on resistors. Second option is to use the dv / dt or sine-wave filters to smooth the inverter output waveforms. Analysis and simulations have been carried out to verify the proposal.

Abstract: This paper presents the results of an investigation into using a commercially available active gate driver integrated circuit (IC) in variable frequency drive (VFD) applications. The gate driver provides multiple steps of gate current levels to control the gate charge of insulated-gate bipolar transistors (IGBTs) during turn-on transitions to adjust dVce/dt, dic/dt and turn-on energy loss. This provides a means for optimizing switching losses, reverse recovery current of the freewheeling diode, and EMI emissions. Experimental results are provided to demonstrate the advantages over a conventional fixed-resistance gate driver. Preliminary simulation results are provided to illustrate the benefits for IGBT junction temperature reduction.

Abstract: An all‐electric ship power system with variable frequency drive and adjustable speed drive generates electric noise in many different forms, influencing the power quality in the ship's service power distribution system. For shipboard power generation and distribution‐related harmonic management both voltage and current harmonic limits must be established. Electrical power system total harmonic distortion (TDH) calculation software is commercially available to determine various drive configurations, such as 6‐pulse, 12‐pulse, and 18‐pulse systems. Equipment that can cause harmonic distortion includes AC or DC adjustable speed drives (ASDs), soft starters, power supplies, silicon controlled rectifiers (SCR) and solid‐state frequency and voltage converters. IEEE Std 519‐1992 provides detailed understanding of harmonics, with examples to calculate harmonic levels. In distribution systems the acceptance limits for voltage harmonic distortion shall correspond to IEC 61000‐2‐4 Class 2. The 6‐pulse drives are used with filters to minimize the THD level to meet requirements.

Abstract: It is well understood that variable frequency drives (VFDs) can cause overvoltage up to twice the DC bus voltage (2 pu, where 1 per unit is the DC bus voltage) at the machine winding terminals, especially if long power cables are used and/or fast rise and fall times are implemented. If the voltage oscillation is not fully decayed when the next pulse arrives, double pulsing occurs and the overvoltage can go up to 4 pu in one switching event. To prevent the damage of the 4 pu overvoltage to the electric machine insulation system, filters are commonly used between the VFD and the machine. The filters, however, add significant cost and size to the system. The higher dv/dt associated with the increasingly popular wide-bandgap devices requires even larger and more expensive filters to be installed. This paper proposes a new PWM control method, the double pulsing offset technique (DPOT), to restrain the overvoltage peak-to-peaks within 2 pu regardless of the switching frequency or dV/dt of the power semiconductor devices. The need to install filters, therefore, is potentially eliminated with the implementation of DPOT. This control scheme was validated using an accurate reflected wave phenomenon simulation model using finite element analysis (FEA). It was also fully implemented online and offline using a DSP and a SiC-MOSFET -based inverter. The experimental results with various operating conditions of the inverter are presented and analyzed. The results show that DPOT is successful in eliminating double pulsing even in harsh operating conditions such as high dV/dt, long cable length, and frequent polarity reversals.

Abstract: The paper deals with the results of computer simulation of electromagnetic torque of auxiliary induction motors and phase splitters type NVA-55 (4-pole, 55 kW) onboard of AC electric locomotive “Ermak”, which made in Russia. Because of the unbalanced system of electrical voltages (sinusoidal taken as a first approximation), except a constant electromagnetic torque component comprises in all cases the significant harmonic component of 100 Hz frequency, and in cases of squirrel cage broken bars presence - in the time harmonics spectrum frequencies from 10 Hz to 110 Hz. If we take into account non-sinusoidal form of feeding voltages signals then we shall have frequency range from 10 Hz to 700 Hz. As the NVA-55 motor bearing failures are significant, it is assumed that a contributing factor is the cyclic alternating load on the electromagnetic torque ripple causing metal fatigue failure. Proposed to use the AC variable frequency drive based on autonomous voltage inverter with pulse-width modulation control for feeding an auxiliary induction electric machines. This ensures symmetry and three-phase voltage stabilization that provides a constant sign for the electromagnetic torque of the motor with low ripple, shifted to higher frequency range.

Abstract: An intelligent power module includes a rectifying circuit for connecting with a corresponding external AC power source to convert a first AC power transmitted from the external AC power source into afirst DC power; An inverter circuit connected to the rectifier circuit for converting the first direct current into a second alternating current; A control circuit and a driving circuit are connectedbetween the inverter circuit and the control circuit for driving the inverter circuit to operate under the control of the control circuit. As the intelligent pow module controls the circuit, rectifiercircuit, the inverter circuit and the driving circuit are integrated in the whole module, Compared with the existing intelligent power module, the intelligent power module has a higher integration level, which simplifies the hardware circuit design, helps to shorten the development cycle and reduce the volume of the system. Users only need to build a simple peripheral circuit to complete the development of the variable frequency drive system.

Abstract: This paper primarily focuses on the implementation of variable frequency drive (VFD) of the induction motor based upon Indirect Rotor field Orientation (IRFO). The dynamic mathematical model of the induction motor has been developed in MATLAB and then its speed is controlled by implementing the VFD based on IRFO. The IRFO method gives a very precise control over the speed of induction motor. The simulation results are obtained by varying the speed and keeping the load torque constant. This model will largely serves as a basis for developing Induction motor test bed for academia and industry of Pakistan. This test bed would serve as the comprehensive R&D facility in the field of AC machines where both steady state and transient response of the motor can be studied.

Abstract: This paper discusses the speed regulation of using A Variable Frequency Control Induction Motor (VFD). The Variable Frequency Drive (VFD) is a system for electronics. Shift the energy source of the utility to variable frequency to monitor AC motor for operation at variable speeds. The Induction Load the engine is not static. It can vary according to the load, as requirement needed. So, as per increasing or increasing, speed must be altered diminishing the load. If the supply voltage has decreased, the torque of the motor they are also reduced. Motor speed is directly related to frequency of supply. Therefore, to preserve the voltage of the speed supply the frequency and frequency can differ accordingly. There are several ways to describe Drive Variable Frequency (VFD). This essay is intended to have a fundamental understanding of the Variable Conditions of the Frequency Drive (VFD), Variable Frequency Drive (VFD)

Abstract: In the article the mathematical model of the bidirectional DC-DC converter with accounting the incomplete controllability is considered. The article shows that the mode of incomplete controllability appears during the mode changing of DC-DC converter from Buck to Boost and vice versa. It is assumed that the DC-DC converter operates as a part of variable frequency drive and it is used to connect the block of supercapacitors to the DC link of frequency converter. In this case, in the construction of a mathematical model of DC-DC converter it is necessary to consider the DC link model of the frequency converter, which has a significant influence on transients in the system. The developed mathematical model also takes into account the work of the DC-DC converter in DCM and CCM. The paper presents an equations system of mathematical model, block diagram and simulation results of the DC-DC converter. It is shown that the incomplete controllability of DC-DC converter has a significant influence on the transients in the system.

Abstract: Hybrid-power transport refrigeration system (200) having a fixed-speed generator (202), a refrigeration compressor (204), a power bus (208) electrically connecting the fixed-speed generator (202) to the refrigeration compressor (204), an energy storage device (220) electrically connected to the power bus (208) and arranged to receive power from the fixed-speed generator (202) in an engine-operation mode and to supply power to the refrigeration compressor (204) in a battery-operation mode, and a DC/AC variable frequency drive electrically connected between the energy storage device (220) and the refrigeration compressor (204) to convert a DC power supply from the energy storage device (220) to a variable frequency power to drive the refrigeration compressor (204) when in the battery-operation mode.

Abstract: The article considers the problems of calculation and interpolation of the efficiency of a synchronous reluctance fan drive in a wide range of loads. In order to estimate the performance of the fan, a semi-analytical model on the basis of experimental data on the selected operating modes is used. The errors of various approaches for interpolating the data on the efficiency of a variable frequency drive using a limited amount of experimental data is estimated.

Abstract: Novel power factor corrected ac–dc rectifier topologies suitable for induction motor drive based elevator application are proposed. These converters make use of coupled inductor for power conversion and are capable of providing high voltage gain at low duty cycle and high efficiency. The current flowing through the coupled inductor is controlled through a feedback control loop to achieve unity power factor. The total harmonic distortion (THD) value of the current is observed to be approximately 4.8%, which is within the limits prescribed by various standards. With the use of coupled inductor, the voltage stress of the switches operating at high frequency is reduced, which reduces switching losses. The loss comparison with the conventional converters shows a reduction of at least 22% of losses. The proposed scheme also results in reduction of the variable frequency drive's dc-link capacitance value as an ultracapacitor bank is interfaced with the dc link through a bidirectional converter for improving efficiency and providing transient power requirements. This also helps in increasing the reliability and dynamic response of the system. The settling time for a step change in voltage reference is observed to be reduced by nearly 50%. Proposed topologies and schemes are validated through MATLAB/Simulink simulations and experiments.

Abstract: This paper outlines the reduction in energy consumption of motor-driven centrifugal pump systems by optimising key components of the system and controlling these from a system point of view. The latest developments in premium efficiency electric motors with variable frequency drive (VFD) control create an opportunity to retrofit older, motor-driven technology applications such as centrifugal pumping systems in an economically viable manner. A case study utilising a 132kW motor-driven pump installation with a delivery rate of 426m3/hr and servicing a head of 80m is studied, with the results following an energy efficiency upgrade being reported on. Energy efficiency is quantified by employing the International Performance Measurement and Verification Protocol (IPMVP) on the holistic system as opposed to the measurement of individual components as outlined in, amongst other standards for other components, the test methods for determining losses and efficiency of VSD-fed motors IEC 60034-2-3. The IPMVP protocol further provides the parameters for quantifying specific energy consumption improvement of a complete pump system. The pump system supplies water for public use in the northern region of South Africa. An overall energy saving of 36% for the complete pumping system is reported whilst maintaining unchanged water delivery; alternatively water pump station throughput can be increased by 58% without increasing energy consumption.

Abstract: This paper outlines the methodology of designing and implementation of a solar powered system which can be used to make a human comfort zone during day time without using battery backup but with the use of Supercapacitors. Basically, major converter losses are reduced in this system. In acquiring a highly efficient power supply, the charge controller plays an important role. When a DC microgrid powers DC loads based on a renewable source such as a PV system; energy storage becomes mandatory due to fluctuating nature of the source. Localized DC-energy storage within DC-DC converters could address this requirement. A variation of supercapacitor assisted regulators could provide localized energy storage with low-noise and fast transient response [1]. 12 V LED lights will be powered from this system. LEDs can be powered directly via a supercapacitor bank from the regulated Photovoltaic energy. In the case of Inverter type Air Conditioner, in order to overcome converter losses, the DC Bus inside it should be accessed. Typically, DC Bus voltage inside the Variable Frequency Drive (VFD) is 1–414 times the supply voltage. Hence DC-DC Converters are used to power up the inside circuitry of the Inverter Air Conditioner from the solar panel. In order to optimize the energy usage and reduce electricity consumption, light dimming and air conditioning control systems were added to control the light intensity and switching of the air conditioner.

Abstract: The performed studies in the area of petroleum engineering facilitate the shaping of a system of fundamental knowledge that allows the future specialist to scientifically analyze the issues in one’s professional domain, implement the obtained basic knowledge in practice, and independently digest the new information encountered during one’s industrial and scientific activity while employing modern methods of research. Controlling the pressure and flow of fluids in pipelines remains a highly important task. For this reason, further studies to find new designs and technological solutions to optimize these processes are promising and relevant, allowing to increase the technical and economic performance indicators of the processes of supplying pressurized fluid.