Variable Frequency Induction Motor Research Articles

Radiated emission from DC bus loop of AC induction motor inverter FEM based and experimental evaluation

The paper describes practical method how to analyze locally radiated magnetic field to improve the geometry of printed circuit board (PCB) or busbar structure, select better control method and design electromagnetic interference (EMI) filter. Experimental prototype of three-phase induction motor variable frequency drive has been created and controlled by microcontroller with sinusoidal, namely pulse with modulation (PWM) method. Three-dimensional finite element model simulation of DC bus structure has been created and results has been obtained. Electromagnetic field was measured, practically and results compared with simulation-based ones. Simulation based and experimental results matches thus allowing to conclude method usefulness for cost effective way to test different geometries of DC bus, different modulation methods, EMI filters for variable frequency drive, and other power electronics converters.

Stator Turn Fault Diagnosis and Severity Assessment in Converter-Fed Induction Motor Using Flat Diagnosis Structure Based on Deep Learning Approach

This work aims to explore the hybrid deep learning techniques for early interturn fault diagnosis and fault severity assessment in variable frequency induction motor drive. However, the existing literature mostly focuses on identifying the fault patterns, whereas the assessment of fault deterioration before it reaches the extreme degradation state has been less investigated. In this paper, a hybrid structure combining two-dimensional convolution neural network (2DCNN) and long-short term memory/gated recurrent unit (LSTM/GRU) has been modelled as a relatively lightweight flat diagnosis structure (FDS) for early fault identification and its severity assessment simultaneously in converter-fed induction motor. Initially, the hierarchical layers of 2DCNN extract the effective features automatically for fault detection and its severity identification simultaneously. Then, these features are presented as suitable inputs to LSTM/GRU for classification. A comparative evaluation of the proposed hybrid method with the standalone structure, namely 2DCNN, LSTM and SVM proves the advantages of the proposed scheme, and its applicability for both fault diagnosis and fault severity assessment in industrial drive systems, under variable frequencies and load variations.

Influence of active rectifier with relay current circuit on supply voltage distortion

One of the ways of energy supply effectivization is transition from an uncontrolled to a controlled drive. The mineral mining and processing sector widely uses variable frequency induction motor drives. At the same time, operation of the variable speed drives is accompanied with essential distortion of the supply voltage from sinusoid. It is possible to improve the supply energy quality in the mains with variable frequency induction motor drives using active rectifiers. The modeling results are used to analyze the energy quality in the supply mains with a variable frequency induction motor drive and an active rectifier with a relay current circuit. All computations are implemented using a custom ized computer program which includes the properties of frequency conversion with active rectifiers and the supply system characteristics. The calculated results are presented as functions of short-circuit power in the supply system. Such representation enables substantiating the use of active rectifiers with relay circuits in frequency conversion. The recommendations on operation of active rectifiers with relay current circuits in case of supply of frequency converters by low-power systems are given. It is concluded on efficiency of the active rectifier when operating together with a higher harmonics filter. With the filter included in operation of an active rectifier, the mains voltage is nearly sinusoidal, which proves the filter efficiency in operation with the active rectifiers with relay circuits. The found relationships support well-reasoned decision-making on selecting the active rectifier control at the engineering stage of electrical mining machines and facilities with variable frequency induction motor drives.

ANFIS based AZSPWM methods for reduction common mode voltage in asynchronous motor drive

<div class="keywords">Space vector pulse width modulation (SVPWM) is a popular technique in the field of variable frequency induction motor drives. It gives better working and good direct current bus utilization in comparison to the sinusoidal PWM (SPWM) method. However, it decreases harmonic fluctuations and generates high common mode voltage (CMV) fluctuations, which results in common mode currents inside the motor. Hence, the performance of the motor may be deteriorated. To reduce the CMV, this paper presents a family of active zero state PWM (AZSPWM) methods using an adaptive neuro-fuzzy interference system (ANFIS). The proposed approach uses a five-layer hybrid learning algorithm for training the network. The training data is obtained from the classical SVPWM method. To analyze the proposed PWM methods, simulation is carried out using MATLAB and evaluated.</div>

Global fluid flow and heat transfer characteristics analysis of an open air-cooled drive motor for drilling application

The stator winding temperature rise of variable frequency induction motor (VFIM) with high current density may be too high during operation, which properly causes motor breakdowns. Therefore, it is essential to conduct thermal management for VFIM. In this paper, a 600kW VFIM with the open air-cooling is studied at the point of thermal. A compact cooling improvement structure, axial ventilation guide vane, is proposed to strengthen the heat dissipation capacity of the motor. The global numerical model based on the multi-physics bidirectional coupling method is established to provide a comprehensive understanding of fluid-thermal characteristics in the motor. Based on simulation results, the cooling improvement is analyzed and discussed from multiple perspectives, such as temperature, flow, vortex, etc. It is concluded that the proposed structure can reduce the maximum and average temperature rise of the stator winding by 1.4K and 0.7K, respectively. Moreover, the effect of installation location on the cooling effect is investigated. When the proposed structure is installed on both sides, the overall heat dissipation power rises to 42299.7W. The experiment was also conducted to verify the simulation results. The relative error between simulation results and experimental data is 4.4%.

Control of a Waveshaper-MMC With Thyristor-Based Front-End Converter for Open-End Winding Variable Speed Medium-Voltage Induction Motor Drive

For variable frequency induction motor drive application, conventional modular multilevel converter (MMC) faces some issues, like high capacitor voltage ripple at low frequency, high circulating current, and high component count. This article proposes a novel configuration to address these issues, where a six-pulse thyristor-based controlled rectifier is combined with a waveshaper-based MMC (WS–MMC). Each phase of the converter consists of a WS and director valve, and then the phases are connected in series to create a common dc-link. The use of a thyristor-based controlled rectifier as a front-end converter increases reliability and reduces component count to a large extent. Unlike conventional MMC, circulating current does not exist in this converter, and the capacitor voltage ripple does not depend on the operating frequency. As a consequence, the current rating of the switching devices is reduced for the same power output, and capacitor voltage ripple at low frequency stays within the specified limit. Besides this, the component count of the proposed configuration is far less than the MMC-based topologies available so far. The operation principle, relevant control techniques, and analysis of the converter are discussed in detail in this article. The complete system is simulated in MATLAB/SIMULINK, and the performance of the control methods has been validated at different operating frequencies with various load torques. The results show satisfactory performance.

Induction motor efficiency maximizing based on torque per power index

<span>In this paper, efficiency maximization of induction motor variable frequency speed regulation system based on torque per power (TPP) index is proposed. The detail of the mathematical model of the induction motor considering the iron loss and the rotor field orientation, the relationship between the motor torque loss power ratio and the motor speed and slip frequency presented. The functional relationship between the torque loss power ratio and the motor speed and slip is derived, and the derivative is obtained to find the optimal slip frequency corresponding to the maximum value. The simulation model and experimental platform of the control system were built in Matlab/Simulink to verify the effectiveness of the method. The result approved the torque loss power ratio takes the maximum value, the high energy efficiency operation with the minimum power loss of the motor control system is realized.</span>

Speed Adjustment on Variable Frequency Induction Motor Using PLC for Automatic Polishing Machine

PT. ROFENTI KARSA TAMA is a ceramic industry that produces products in the form of ceramics from natural stone which are addressed in Winong GEMPOL Village - MALANG. To produce a perfect ceramic process requires absolutely reliable electrical and mechanical equipment. In an automatic system a frequency converter is used as a speed regulator, because in a manual system using a grinder, the capacity is only 0.57Kw (kilowatts), and the production effect is not good. Therefore, the purpose of this study is to design an automatic polishing machine using a PLC-based converter. Based on the PLC, the capacity is 5 or 5 Kw (kilowatts). This system can increase ceramic output and improve quality. In this case, assuming that the operator usually uses an automatic system to complete the work of the three operators, the polishing machine production costs can be reduced. Through system improvement, production quality can be improved, manual polishing operators can only produce 480 pieces per day, while the automatic system can produce 1,536 pieces. One day, the polishing operator will save production costs of Rp 2.7 million per month.

Smart Induction Motor Variable Frequency Drives for Primary Frequency Regulation

This article proposes an induction motor variable frequency drive to investigate its potential in handling smart grid's frequency. This can thus mitigate the grid reliance on expensive power plants. To this end, a primary frequency controller is presented enabling the drive to reduce its power in proportion to grid frequency drop. The dynamic limitation of the drive due to load's inertia is considered through a motor's speed rate limiter. Moreover, an appropriate inertia emulator is proposed for the smart drive by inspiring the inertial response of a direct-on-line motor. The impacts of speed rate, maximum reserve power and motor driven load's inertia on dynamic behavior of the smart motor load during the frequency support are addressed. Besides, the effectiveness of the smart drive's contribution in primary frequency regulation of the IEEE 39-bus test system is explored. In this regard, a critical droop coefficient that guarantees the maximum reserve power delivery for the smart drives is analytically derived. Finally, the proposed approach is extended to include the critical droop derivation for a set of smart drives with different sizes and priorities to rank their participation in primary frequency regulation process.

Optimization of the control loops of the variable frequency induction motor drive of the flame reactor feed screw

In the paper the optimization of the control loops of the variable frequency induction motor drive for the feed screw of a flame reactor has been carried out to obtain required dynamic characteristics of the electric drive for known parameters of the plant. Simulation studies of basic control loops

Analysis of the dynamic performance of a variable-frequency induction motor drive using various control structures and algorithms

A comparative analysis of the dynamic characteristics of field-oriented induction motor drive control systems relying on the main magnetic flux linkage vector reference, space-vector pulse width modulation (SVPWM) of the voltage inverter output, and direct torque control (DTC) is carried out using the Matlab/Simulink program package, with the parameters of the induction motor model used being the same. A changeover from stepless vector control systems to systems using microprocessors and modern controllable frequency converters operating on the principle of relay control entails possible changes in the properties of the electric drives being controlled. In this connection, there is a need to compare the dynamic performance characteristics of an electric drive with a slave vector control system (with an idealized frequency converter), referred to as electric drive 1 (ED1), an electric drive with a DTC system (ED2), and an electric drive using direct torque control and SVPWM (ED3). Modeling has shown that the response time of the torque control loop in all the control systems considered is the same, the time delay being no more than 0.01 s. On the whole, speed control transients in all of the above systems take their course in one and the same way. The differences in flux linkage control transients between ED2 and ED3, on the one hand, and ED1, on the other hand, are due to the differences between the methods used to form the electromagnetic torque. No provision is made in the above control systems for the stabilization of the magnitude of the flux linkage vector. At low loads, the flux linkage automatically follows the load. In an ED3 with direct torque control, the calculation of the necessary instant magnitudes of the voltage vector projections and the SVPWM based formation of the voltages applied to the motor allows implementation of a fast-response control system with minimal harmonic distortions and torque pulsations. The control system coefficients are calculated beforehand. The speed controller is adjusted to the technical optimum. In the main flux linkage oriented control system, it is also desirable to use an SVPWM-based formation of the motor voltage.

Simplified variable frequency induction-motor drive model for power system stability studies and control

Abstract: Powerful variable frequency drives (VFD) are becoming more widely used in power systems. However, there are only a few works addressed to VFD motor dynamics that are suitable for large-scale power system stability studies. The paper proposes a fundamental frequency simplified model of the VFD, which provides an adequate modeling for the study of electromechanical transients in large-scale power systems. Its implementation was carried out in Power System Toolbox (PST), an open source software available for both scientific and commercial purposes. The model was complemented by a number of protection and control strategies that allow to perform adequate modeling for severe disturbances.

Intelligent Neural Network Control Strategy of Hydraulic System Driven by Servo Motor

Abstract A novel intelligent neural network control scheme which integrates the merits of fuzzy inference, neural network adaptivity and simple PID method is presented in this paper. This control method overcomes the defects existed in the traditional variable frequency induction motor driven hydraulic source, such as slow response, poor control precision, easy to overshoot. Permanent magnet synchronous motor driven constant pump hydraulic system is designed instead of common motor, energy saving, fast response and easy to realize closed loop control. System uses the structure of the combination of neural network control and RBF network online identification. The parameters of the controller are optimized by PSO algorithm offline and error back propagation (BP) algorithm offline, and a RBF network is built to identify the system online. The hydraulic power system’s control simulation experiments are conducted, and the experimental results at the typical working conditions of the hydraulic source show that the controller and its optimization algorithm can effectively improve the system performance, and the system has no steady-state error, good dynamic performance and good robustness, superior to conventional fuzzy controller and PID controller.

MexBIOS – среда разработки современных систем управления электроприводов

In the paper the principle of design and implementation of tools for developing and debugging the software of modern digital control systems of high-accuracy electric drives has been considered. Difficulty of learning and implementing the programming languages puts additional barrier for technical specialists, who are realising new ideas in field of control systems for complex electromechanical objects. Ready-to-use software complex MexBIOS provides significant reduction in time-to-market of electronic control units, achievement of required load characteristics and cost decrease of microprocessor control systems for electric drives. The software complex is an integrated environment of computer-aided design with ability to debug and adjust digital control systems for electric drives. Earliest versions of MexBIOS enable development of microprocessor control systems for electric drives in real-time mode, but programs, which have been developed by means of MexBIOS, were cumbersome. To provide visualisation and ease of understanding of the program flow a new concept of the designing the structure of the software complex have been elaborated. Now it is possible to implement complex algorithms. In late versions a new feature of state-flow programming has been added, i.e. of choosing separate states of the object and describing rigorously the control system actions in terms of these states. At present the program code can be modified without stopping the program run in order to modify the program structure of the control system without stop of the manufacturing process. The analytical relations and the synthesis procedure of vector control system for variable-frequency induction motor by visual programming method in new software environment MexBIOS have been developed.

Application of Fuzzy-PI Controller in the Asynchronous Motor

This paper proposes an induction motor variable frequency speed control system based on fuzzy-PI self-tuning. The system includes coordinate transformation modules, vector control modules, space vector pulse width modules, fuzzy-PI self-tuning speed regulator, excitation current and torque current PI regulator. Because the speed regulator controlled by the fuzzy-PI self-tuning has better control effect than traditional PI. The performance can be reflected by the shorter response time, smaller overshoot. In addition, when the load torque changes, the electromagnetic torque changes more smoothly and does not have large fluctuations.

Performance of a Self-Excited Induction Generator With DSTATCOM-DTC Drive-Based Voltage and Frequency Controller

This paper presents the performance of a self-excited induction generator (SEIG) with a voltage and frequency controller (VFC) in a standalone microhydro power generating system. The VFC consists of a distribution static compensator (DSTATCOM) and a direct torque controlled variable frequency induction motor drive (VFIMD) operating as an electronic load controller (ELC). The DSTATCOM is an insulated-gate bipolar transistor-based three-leg voltage source inverter with a self-sustaining dc bus. The main objective of DSTATCOM is to regulate the system voltage through reactive power compensation. In addition to voltage regulation, the DSTATCOM compensates the harmonics generated by nonlinear loads as well as ELC. The ELC controls the system frequency through the active power balance. The VFIMD of the ELC drives a pump and it consumes the power in excess of consumer load power to maintain constant power generation at the SEIG terminals, which in turn regulates the system frequency. A prototype-proposed VFC is developed and tested with a variety of loads. Experimental results demonstrate that the proposed VFC can effectively control the system voltage and frequency.

Investigation of Vibration Signatures for Multiple Fault Diagnosis in Variable Frequency Drives Using Complex Wavelets

Embedded variable frequency induction motor drives are now an integral part of any industry due to their improved speed regulation and fast dynamic response. Hence, their diagnosis becomes vital to avoid downtimes and economic losses. In this paper, a technique based on a recent enhancement on wavelets, known as complex wavelets, is proposed for identifying multiple faults in vector controlled induction motor drives (VCIMDs). Radial, axial, and tangential vibrations are analyzed for diagnostic purpose. Initially, a relatively simple thresholding based method is investigated for feasibility of diagnosis under variable frequency and load conditions. In the second part, the feature extraction and classifier modeling are discussed, in which the nearly shift-invariant complex wavelet based model is compared with the discrete wavelet transform (DWT) for its applicability in detecting multiple faults. The fault conditions considered here are the most prominent ones such as interturn fault, interturn fault under progression, and bearing damage. Comparable performances of support vector machine (SVM) based models and simple technique based on k-nearest neighbor (k-NN) show the importance of efficient representation of input space by analytical wavelet based feature extraction. The performance indexes show the applicability of the scheme for industrial drives under variable frequencies and load conditions.

Model and Conditional PID Compensation Control on Flow of Hydraulic Source Driven by Permanent Magnet Servo Motor

In view of the existed defects of hydraulic source driven by variable frequency induction motor in practical applications, such as slow response, low control accuracy and difficult to master control parameters, a flow control strategy of permanent magnet servo motor driven constant pump hydraulic power unit is presented. This strategy mixes merits of permanent magnet servo motor, such as good dynamic characteristics, high control precision, and saving energy, and characteristics of constant pump, such as simple structure, good reliability and strong ability to fight pollution, etc. According to the relationship between speed, flow and pressure of constant pump, and oil temperature, viscosity, elastic modulus and other related parameters, model and conditional compensation proportion, integration, differentiation(PID) control on motor speed is proposed, through which the rapidity and accuracy of control on the output flow of constant pump are realized easily. The control system makes full use of the stability and timeliness of the open-loop model control to approaching target flow, overcoming the adverse effect that the measured flow signal delay brings serious hysteresis influence on system response in the traditional flow control system. In addition, the conditional PID compensation control, through the comparison with the conditional threshold value to open, can further eliminate flow deviation and improve the precision of the system. Simulation results show that the feasibility of the model control and the conditional PID compensation control. Experimental results show that the response of model control is close to motor speed open-loop control, which is better than indirect measurement flow feedback control, and significantly ahead of the turbine flowmeters measured flow feedback control. The control system has good resistance to load disturbance ability; the conditional PID compensation control can completely eliminate the steady-state error caused by the system parameter nonlinear change and simplified model, and can follow target flow at slope response without error.

The Study of Parameter Robustness of Induction Motor Variable Frequency Speed Regulation Adaptive Inverse Control System

Aiming at the problem that the existence of the time varying parameter in the induction motor variable frequency speed regulation system influence the induction motor speed control performances through influences on the vector control decoupling performances, the author puts forward the solution that is to apply the adaptive inverse control scheme to the induction motor speed control system. Research findings suggest that adaptive inverse control is of high parameter robustness to both gradient parameter perturbation and mutational parameter robustness, which effectively reduces induction motor time varying parameters influences on dynamic and static performances of the frequency speed regulation system.

Design of Induction Motor Variable Frequency System Based on DSP

As the development of the Microprocessor technology, Power electronic technology, Motor manufacturing technology and modern control theory, Variable frequency system is used more and more widely.This paper introduces a design of motor variable frequency control system．AC-DC-AC-circuit is used in its main circuit, and U/F control strategy is used in its controlling method．Based on the system parameters，the calculation and selection of the component parameters are carried out．Finally，the intelligent power module(IPM)is used as a power inverter circuit switching devices and TI DSP(TMS320LF2407A) is as a core control to improve the precision and stability．The experimental result indicates that the driving system has the stable performance, high anti-interference and high value.