Showing papers on "Variable-frequency drive published in 2016"

Fracturing system layouts

Abstract: Systems for stimulation of a formation include a variable frequency drive (116) configured to receive and output medium voltage power (118) and in communication with high pressure pump (112). A variable frequency drive actuates an electric motor (114) associated with the high pressure pump, such that the pumps pressurizes a fracturing fluid, proppant, or combinations thereof for flowing the fracturing fluid, proppant, or combinations thereof into the formation.

Analysis of elevator drives energy consumptions with permanent magnet machines

Abstract: This paper examines the energy consumption of the electric drives and permanent magnet machines considering the actual system performance of machine and variable speed drive. Most common solution in the current trend of elevator technology is permanent magnet synchronous motor with variable frequency drive with direct current voltage bus intermediate. Energy consumption has been understand with actual measurements and examine the behavior to understand the load on the system that would be higher efficient.

Simulation of cable charging current and its effects on operation of low power AC drives

Abstract: In Variable Frequency Drive (VFD) systems, long motor leads can have many detrimental effects, including cable charging current, overvoltage at the motor terminals, and voltage stress on power modules. Different types of AC system grounding can also interact with long motor leads to yield undesirable effects on drive operation. Analyzing models of various components of a drive system is useful to determine any potential issues prior to installation and to recommend any needed filter solutions to mitigate these issues. However, prior cable models have several shortcomings and are inadequate for fully understanding long cable effects prior to VFD system installation. In this paper, a commercially available finite element analysis (FEA) tool is applied to generate a wide frequency range model for a multi-conductor VFD cable. It is shown that this cable model can be used in a system level simulation to determine application issues for low power AC drives. The method is validated using experimental tests on selected cable, motor and drive combinations.

Innovative design and feasibility study for a subsea electrical submersible pump system

Abstract: In this paper, a subsea electrical submersible pump (ESP) system with challenging long cabling requirement is designed. Several factors are considered for the design: configuration of the system, length and size of the subsea cable, and load filter parameters for a medium voltage variable frequency drive used in the system. The system requires a 4 km or a 50 km subsea cable connected to the output of the drive. With such long cables, harmonic resonance and motor start-up are two major concerns. Various system designs are investigated through a feasibility study by computer simulation, which includes a steady-state analysis, a frequency response analysis, and a motor starting study. New designs of the load filter for the medium voltage drive are proposed due to unsatisfactory performance of its original standard load filter from the drive manufacturer. The frequency response analysis combined with the steady-state analysis are used to evaluate the effectiveness of new load filters. The motor starting study determines the possibility if the motor can start-up successfully for a system design. The acceptable designs of the system are finalized based on results of the feasibility study.

Analysis of elevator drives energy consumptions with permanent magnet machines

Abstract: Vertical transportations in a facility is one of the sources, which consume electrical energy. In this script, it examines the energy consumption with permanent magnet machines considering the actual system performance integrated with variable speed drive. Most common solution in the current trend of elevator technology is permanent magnet synchronous motor with variable frequency drive with direct current voltage bus intermediate. Energy consumption has been proposed to be understood with actual measurements and dynamic behaviour on various loads on the system is studied. Further, the proposal is to understand the regimes that would be higher efficient, which is analysed and presented.

Dynamic performance of air conditioners with variable frequency drive

Abstract: This paper presents laboratory test results of commercially available air conditioners with variable frequency drives (AC-VFD). These air conditioning systems are furnished with a variable frequency drive module between the input terminals and the compressor. These systems are typically referred to in the market as “ductless air conditioners”. First, this paper will present the test setup and the test equipment used during the tests. Additionally, it will provide the test results for various tests including start-up, dynamic performance during voltage and frequency events, and harmonics contents. Finally, it will provide recommendations on how these devices can be enhanced to be more grid friendly and to support the grid during emergencies. The test results and information obtained in this paper can be used to develop, test, and validate computer dynamic models use for bulk system studies by system planners and/or researchers. In addition, it can be used to persuade the industry on needs from these types of equipment.

System and method for starting a variable frequency drive with reduced arc flash risk

Abstract: In one embodiment, a variable frequency drive system includes a main contactor, a variable frequency drive, a charging module structured to generate a magnetizing AC voltage, wherein the charging module is structured to selectively provide the magnetizing AC voltage to a transformer of the variable frequency drive, and a sensing and control circuit having a number of sensors operably associated with the variable frequency drive. The sensing and control circuit is structured to detect a short circuit condition in the variable frequency drive when the magnetizing AC voltage is provided to the transformer based on an output of at least one of the number of sensors, and responsive thereto prevent the main contactor from being closed and thereby prevent the main AC voltage from being provided to the transformer.

The effect of sampling rates on the performance of a three phase PWM inverter and choice of appropriate sampling rates

Abstract: Pulse Width Modulated (PWM) inverters are most commonly used for grid interfacing in renewable energy systems and for speed control of induction motors in Variable Frequency Drives (VFD), wherein the control computations are implemented in digital signal controllers (sample-based in nature) and are highly complicated. Sampling interval is a critical parameter in PWM control algorithms, because the controller is required to complete one set of control computations within one sampling interval. This is owing to the fact that PWM control algorithms typically involve several axis transformations during a single sampling interval, and consequently take up thousands of instruction cycles, as the trigonometric transformation equations are implemented in modern processors using iterative procedures. This paper presents the effect of sampling frequency on the performance of a PWM inverter in a VFD for speed control of an induction motor. A step by step procedure for sampling rate selection is also proposed. A simulation study is done using MATLAB/Simulink to analyze the performance of the PWM inverter under variable frequency operation. At a fundamental frequency of 50 Hz, a substantial reduction in the THD, by about 9.12% in the voltage and about 39.01% in the current is observed with the proposed increase in sampling frequency by about ten times. Also, a reduction in the % error in voltage by about 5.3% is observed.

Regenerative variable frequency drive with auxiliary power supply

Abstract: A regenerative variable frequency drive includes an active converter connected to a DC bus that is connected to a first inverter that converts DC power to variable frequency, three phase AC power, and variable frequency, three phase AC power to DC power, and to a second inverter that converts DC power to three phase AC sine wave power. The converter converts single phase AC power to DC power and DC power to single phase AC power, and maintains a selected voltage on the DC bus. The converter has an active rectifier and a controller that drives the rectifier with a pulse width modulation according to a hybrid voltage switching scheme that switches the rectifier according to a unipolar voltage switching scheme through most of each cycle and switches the rectifier according to a bipolar voltage switching scheme around each zero crossing.

Harmonic mitigation in AC motor using multi-pulse rectifier

Abstract: Now-a-days, sustainability of power quality is a major concern. Speed control of an AC motor is required for several industrial applications, but is often difficult to achieve as the AC motor runs at fixed speed. Hence, power electronic devices are introduced in the system. Due to the development in power electronic devices with improved dependability and cheaper cost, results in the growth of modern variable frequency drive (VFD) which can control the speed of an induction motor by adjusting the frequency of the machine [8]. They produce harmonic components and distort the supply mains, which in turn adversely affect the power quality. To outlive the difficulty, a technique named multi-pulse rectifier is developed. The main objective of this work is to reduce the impact of harmonic distortion using variable frequency drives (VFDs). Modeling, simulation and performance analysis of VFD is done based on Total harmonic distortion (THD) [8]. The proposed topology deals with the THD comparison for 6, 12 and 24 pulses. All the simulations are carried out in MATLAB/Simulink.

Simulación del inversor multinivel de fuente común como variador de frecuencia para motores de inducción

Abstract: This paper describes the simulation of a three-phase multilevel common source converter of 15-line levels, as variable frequency drive for fed induction motors. The variable frequency drive is optimized in the first 50 harmonic responses; the optimization algorithm was developed in Matlab. The simulation results validate the benefits of this kind of fed induction motor with regard of the power quality in both: voltage and electrical current behaviour.

Testing device for control panel of variable -frequency drive

Abstract: The utility model provides a testing device for control panel of variable -frequency drive contains power control?section, power strip, discharge resistance, test private circuit board, operating panel, host computer and host computer testing software, control panel fixing device, test?probes, box Power control?section controlling means's powering up and down passes through discharge resistance and realizes the repid discharge when falling the electricity The power strip with 220V input power switching over for + 15V, 5V, 24V power offer and survey test panel It passes through the probe and is observed and controled plate making to be connected to survey test panel to through 232 serial portss and upper computer connection Operating panel passes through the probe connector control panel Host computer software is through stopping with opening of survey test panel communication control test to show the test result The utility model provides a measure because of the manual work, appear that efficiency of software testing is lower, the big scheduling problem of error

Closed-transition variable-frequency drive apparatus and methods

Abstract: A system includes a variable frequency drive (VFD) comprising an inverter having an output configured to be coupled to a motor and a switch configured to couple a power source to the motor to bypass the VFD. The system further includes a control circuit configured to synchronize the VFD to the power source, to operate the switch to couple the power source and the VFD in parallel and to subsequently disable the inverter responsive to a current of the inverter. In some embodiments, a PWM frequency of the VFD may be temporarily increased when transferring the motor from the power source to the VFD.

Fuel cell system ride-through of electric grid disturbances

Abstract: A fuel cell system includes a fuel cell assembly configured to generate a direct current (DC) signal. The fuel cell system also includes one or more inverters coupled to the fuel cell assembly by way of one or more first bus lines. The fuel cell system also includes a variable frequency drive (VFD) coupled to an output of the one or more inverters and configured to receive AC power from the one or more inverters. The VFD is configured to convert the AC power to DC power and to provide the DC power to at least one auxiliary component during a normal operating condition. The fuel cell system further includes one or more second bus lines configured to receive the DC signal via the one or more first bus lines and to provide the DC signal to the VFD to power the at least one auxiliary component during a low voltage ride through condition.

Harmonic reduction, power factor improvement and speed detection for 3-phase induction motor drive system

Abstract: Conventional Variable Frequency Drive (VFD) method for induction motor consists of nonlinear loads such as rectifier and inverter (AC-DC-AC). These nonlinear devices are the biggest cause of harmonics generation on power lines. In proposed system, passive LC filters are used to control the harmonic currents present on power lines. DSP-based variable frequency drive is designed using DSP TMS320LF2407Aoffers an advantage of high speed operation. This paper represents Harmonic Reduction and Power Factor Improvement technique for 3-phase Induction Motor drive system using passive LC components. Sensorless speed detection is achieved based on the analysis of blocked voltage across the non-conducting thyristors. Experimental results are taken in laboratory using 3-phase, 1Hp, 1500rpm Induction Motor. Proposed system for Harmonic Reduction is also simulated using MATLAB/SIMULINK power system toolbox.

Influence of defects in windings insulation on its operation reliability

Abstract: Low-voltage induction motor is one of the most widely used types of electrical machines. Today more and more end users demand reliable and energy efficient electrical machines as an extra feature. Design and applying of control systems for improving energy efficiency must be in correlation with reliability requirements; it is necessary to fetch out the changing operation conditions that can lead to unexpected failures, and to prevent them. This paper describes the influence of insulation defectiveness on winding insulation system reliability in PWM based regulation applications. Currently, the influence of technological defects in the winding insulation on its reliable operation in motor being part of the variable frequency drive has not been thoroughly studied. The relevance of this research is determined by the need to study the “healing” of winding insulation through defects by the impregnation, and its influence on the mean time to failure. The study results will permit to give recommendations for improving the reliability of low voltage windings and subsequently the reliability of induction motors fed by PWM invertors. The study was carried out using a test technique adapted to variable frequency drives and applied to insulation system “varnish — enamelled winding wire”. The experimental results are presented and the main findings are discussed.

Cloth microwave heating drying apparatus

Abstract: The utility model discloses a cloth microwave heating drying apparatus. It includes the microwave oven, the feeding roller, the discharge roller, the variable frequency drive motor, exhaust wet fan, the heat extraction fan, a weighing sensor and a temperature sensor, the temperature controller, PLC controller and humidity transducer, the feed inlet and the discharge gate punishment of microwave oven do not are provided with the feeding roller, the discharge roller, the feeding roller, the discharge roller all links to each other with the variable frequency drive motor, be provided with temperature sensor in the microwave oven, temperature sensor passes through the temperature controller and links to each other with the PLC controller, the PLC controller still with the microwave oven on exhaust wet fan, the heat extraction fan links to each other, the discharge gate department of advancing of microwave oven still is provided with humidity transducer, humidity transducer passes through the PLC controller and links to each other with the variable frequency drive motor. The utility model discloses simple structure can conveniently control heating temperature and input speed, guarantees that the cloth heating is even, and its stoving is effectual.

A new normal mode dv/dt filter with resistor failure detection circuit

Abstract: Insulated Gate Bipolar Transistors (IGBTs) will soon be replaced by wide band gap devices (SiC and GaN) as the choice for power semi-conductor switch in Voltage Source Inverters. These devices have extremely fast rise time and fall time compared to IGBT devices. The high dv/dt of PWM outputs create excessive voltage stress in the insulation system of AC motors due to voltage reflection issues associated with motors at large distances from the drive. In many oil field applications, the distance between the motor and the Variable Frequency Drive (VFD) approaches 300m. In walking rig applications, it is common to use multiple smaller sized conductors per phase, bunched together, to achieve the desired ampacity. This practice results in higher than usual value of the cable parasitic capacitance. Traditional dv/dt filters used for mitigating over-voltage at motor terminals, have been found to be inadequate in reducing the over voltage at the motor terminals in such oil field installations. The damping resistor often experiences high voltage and gets damaged. A new dv/dt filter suitable for use with high power AC motors at distances nearing 300m with a built-in resistor failure detection circuit is proposed here. Test results are given to demonstrate its efficacy.

Reduction of Components in New Family of Diode Clamp Multilevel Inverter Ordeal to Induction Motor

Abstract: This paper describes the design and implementation of a new diode clamped multilevel inverter for variable frequency drive. The diode clamp multilevel inverter has been widely used for low power, high voltage applications due to its superior performance. However, it has some limitations such as increased number of switching devices and complex PWM control. In this paper, a new topology is proposed. New topology requires only (N-1) switching devices and (N-3) clamping diodes compared to existing topology. A modified APO-PWM control method is used to generate gate pulses for inverter. The proposed inverter topology is coupled with single phase induction motor and its performance is tested by MATLAB simulation. Finally, a prototype model has built and its performance is tested with single phase variable frequency drive.

Motor drive method and system of pumping unit under unconventional working system

Abstract: The invention discloses a motor drive method and system of a pumping unit under an unconventional working system, and belongs to the field of oil production engineering. According to the method, a power frequency drive mode is adopted for whole-cycle operation of a crank, and a variable frequency drive mode is adopted by non-whole-cycle pumping operation of the crank and non-whole-cycle non-pumping operation of the crank. The system is provided with a power frequency circuit and a variable frequency circuit with common input and output, wherein input ends of the power frequency circuit and the variable frequency circuit are connected to a power frequency power supply circuit and output ends are connected to a drive motor of the pumping unit; a frequency converter is arranged on the variable frequency circuit; and an operational control unit is also arranged outside the power frequency circuit and the variable frequency circuit. By the motor drive method and system, motor drive means of the pumping unit under the unconventional working system are provided; the actual working time of variable frequency drive can be shortened and the working intensity of the frequency converter can be reduced under the condition that the actual production speed requirement is not equal to a power frequency speed; the heat dissipation condition of the frequency converter is effectively improved; and the equipment lifetime of the frequency converter is prolonged.

Wireless RF Module Speed Synchronization of Multiple Motor’s in Industries based on PLC and SCADA

Abstract: Multiple motor in industries like textile mills, paper mills and steel plants etc. use conveyer belts, for the synchronization of motor to maintain constant loads. This is achieve by interfacing independent PLC to each motor with a speed sensing arrangement with PLC, variable frequency drive (VFD) along with SCADA system. In this paper, prototype hardware is developed and their performance is seen. The objective of this paper is to synchronize the speed of multiple motor in industries using programmable logic controller (PLC) and Supervisory Control and Data Acquisition system (SCADA). The whole information of each motor will be displayed on SCADA screen like, RPM, motor ON/OFF and speeds mismatch display and alarm system.

Air conditioner variable frequency drive system based on multi-winding permanent magnet motor

Abstract: The invention discloses an air conditioner variable frequency drive system based on a multi-winding permanent magnet motor, and the system comprises the permanent magnet motor with N groups of three-phase windings, a control device and N variable frequency devices. The input ends of the N variable frequency devices are respectively connected with a power grid, and the output ends of the N variable frequency devices are respectively connected with the N groups of three-phase windings of the permanent magnet motor, wherein N is not less than two. The control device is used for respectively obtaining the position signals and speed signals of all three-phase windings of the permanent magnet motor, and enables the position signals and speed signals of all three-phase windings to the corresponding variable frequency devices. The N variable frequency devices are used for respectively supplying corresponding voltages to the N groups of three-phase windings according to the position and speed signals. When the permanent magnet motor needs to supply big power, the number of permanent magnet motors does not need to be increased, and the size of a large-power air conditioner variable frequency drive system is prevented from being too large.

Simulation of the aging process of insulating systems variable frequency drive

Abstract: The paper deals with the intensity of the model in the electrical insulation variable frequency drive controlled at different temperatures and electric fields. It is shown that aging of insulation mechanism associated with the development of corona discharges caused by transients when the frequency adjustment. Laws aging of insulation can be described from the point of view of the theory of thermal destruction of dielectrics vibrations.

Influence of VFD parameters on voltage stresses in low voltage windings

Abstract: Currently the frequency control is widely used to provide high level of induction motors efficiency. Studies show that typical for the variable frequency drive (VFD) severe electro-thermal stresses influencing on the windings insulation negatively affect the windings reliability. The need to thoroughly study the impact of influencing factors and to develop possible ways to minimize this impact stipulates the relevance of conducted research. In this paper the influence of the VFD parameters on the level of voltage stresses affecting the insulation of low-voltage induction motor windings is studied. The study of nature and magnitude of electrical stresses was carried out by building a simulation model in the graphical programming environment Matlab Simulink. The modelling results are presented and the main findings are discussed in this paper.

Getting the Most from a Variable Frequency Drive: The Optimal Way to Improve Lifetime and Reliability

Abstract: When using a three-phase variable frequency drive (VFD) powered from a single-phase ac source, the drive's output power has to be limited to prevent higher component stresses in it and in the input power system. To address this issue, many VFD manufacturers derate the drive. Typically, based on the dc-bus-voltage ripple, the output frequency of the drive is limited so that the capacitors are not overstressed. This method does not take into account the stresses in other VFD components, especially the input diodes and terminal blocks. In this article, a new method of protecting the drive using the motor q-axis current is proposed. The motor q-axis current has information that is relevant to the stresses in various parts of the VFD, including the input diodes, input terminal block, and the dc bus capacitors. The output power can be limited by reducing the output frequency based on the average and ripple amplitude of the q-axis current instead of the dcbus-voltage ripple. The traditional dc-bus-voltage-ripple-based fold-back method is experimentally compared with the proposed method using a VFD fed from a single-phase ac source to prove the concept.

Development and testing of 1MW variable frequency drive

Abstract: With the change in scenario of continuous thrust for the improvement of efficiency of the overall system, motors are being coupled with variable frequency drives (VFD) to achieve energy savings, reduced wear and tear on motors, reduction of maintenance cost of mechanical flow controls etc. To meet the market requirements in the low voltage segment, 1MW, 690V ac drive has been developed. The system was successfully tested for V/f control, sensor-less vector control, power on ride through and catch on fly. Various issues related to testing of the machine with open loop v/f control and sensor less vector control were addressed successfully. Load testing of the 1MW VFD also completed with back to back test facility. This paper presents the development and testing of the developed 1MW VFD with the experimental results.

A harmonic suppression method of variable frequency drive based on bacterial foraging algorithm

Abstract: A harmonic suppression method of variable frequency drive VFD based on bacterial foraging algorithm is developed in this study. The objective function to minimise total harmonic distortion THD with certain constraints is established. In order to solve a series of nonlinear transcendental equation, use bacterial foraging algorithm to get the optimal switching time in a certain frequency range and different load to determine the switching time of the inverter power devices. The simulation and experiment results show that the application of bacterial foraging algorithm can more effectively suppress the harmonic amplitude in theory, and the total harmonic distortion is smaller.

Apparatus and method for controlling power in offshore plant

Abstract: The present invention relates to a power controlling device and a power controlling method for an offshore plant wherein a vessel monitoring and control system (VMS) calculates a power limit with consideration of a drilling process and transmits power controlling signals to a variable frequency drive (VFD) according to the calculation. According to an embodiment of the present invention, provided is a power controlling device for an offshore plant including a drilling equipment controller receiving a command for drilling equipment from a worker and transmitting information with respect to power necessary for executing the command to the VMS; a VMS calculating power limits of a plurality of motors of the drilling equipment based on a current power output of the offshore plant, the current power consumption of the offshore plant, and a coefficient according to the drilling process and transmitting power controlling signals to the VFD in accordance with information with respect to the power limit and the power necessary for executing the command; and the VFD receiving the power controlling signals and controlling the plurality of motors in accordance with the power controlling signals. The coefficient according to the drilling process is a preset value for the drilling equipment according to the drilling process. The purpose of the present invention is to provide the power controlling device and the power controlling method for the offshore plant enabling a stable drilling work by supplying sufficient power to the drilling equipment.

Green building air conditioning system with Variable Frequency Drive and Variable Air flow controller

Abstract: The major consumer of energy in any commercial building or complex is Air conditioning A novel air conditioning solution has been developed by IIT Madras to reduce the energy consumption in air conditioning The concept has been piloted and tested for practical viability in IIT Madras Research Park, A 12 million square feet R&D building initial results of which are discussed in this paper Traditionally, in large offices and office space there is problem of either over cooling or under-cooling of specific space Apart from this, the consumer does not have any direct control over setting the local temperature as per their requirements As a result, they end up working in an uncomfortable environment More often than not, in these large offices, large portions are left unoccupied and cooling these zones becomes a waste of energy In this context, the paper discusses the concept of Variable Frequency Drive (VFD) to drive the air handling unit motors and introduces Variable Air-flow Volume (VAV) unit which helps in cold air balancing by cutting off the air supply in an unoccupied zone In addition, this paper describes the power consumption scenario of a typical HVAC system and explains how this innovation can bring about 40% power savings in air-distribution as compared to that for the typical systems This paper also discusses how such a system can be monitored remotely and controlled through an Air-conditioning Management System (AMS), which may be integrated with Building Management System (BMS) Further, the concept of chilling water during the night time when grid-power supply is surplus and storing it in an Insulated Thermal Storage Tank at 6°C, developed by IITM Research Park, is also highlighted in this paper

Experimental Investigation of a Six-Phase Variable Frequency Drive

Abstract: Experimental results of a variable frequency drive, consisting of a six-phase voltage source inverter and six-phase asynchronous AC motor are presented in this paper. Frequency converter uses a six-phase space vector PWM scheme created by the author. The voltage forming scheme is implemented in Matlab/Simulink, and logical signals for inverter control are transferred from PC via the National instruments PCI-6024E data acquisition card. Voltages, at which the experimental motor operates at maximum efficiency, were determined experimentally. Motor transitions, when it is operating with one, two, and three failed phase windings are presented, confirming that a six-phase motor can operate with up to three failed windings.