PWM Voltage Source Inverter Research Articles

Modeling and Simulation of a Carrier-based PWM Voltage Source Inverter for a Nine Phase Induction Machine Drive

The analysis of a carrier-based PWM two level voltage source inverter for a nine phase induction machine drive system is presented in this paper. Methods for generating zero-sequence signals during balanced and unbalanced condition are established. Simulation results for the analysis are presented. Two fault conditions involving the voltage source inverter and the nine-phase squirrel cage induction machine load are investigated. For the two fault scenarios considered, the effects on the performance characteristics of the induction machine load are highlighted. The simulation results obtained show that the two imbalance conditions considered result in substantial oscillations on the electromagnetic torque of the machine with attendant reduction in the torque rating. There is also large slip in the rotor speed. DOI: http://dx.doi.org/10.11591/ijpeds.v5i1.6175

Modeling and Simulation of a Carrier-based PWM Voltage Source Inverter for a Nine Phase Induction Machine Drive

Modeling and Simulation of a Carrier-based PWM Voltage Source Inverter for a Nine Phase Induction Machine Drive

Maximum Power Point Tracking for Grid Integrated Variable Speed Wind based DG System with Dynamic Load

The production of electricity from renewable energy sources like wind energy increases in recent years due to environmental problems and the shortage of traditional energy sources in the near future. This paper presents modeling, simulation and performance study of wind energy based distribution generation (DG) systems for grid connected mode with MPPT controller. The wind power generation system uses wind turbine (WT), a permanent magnet synchronous generator (PMSG), a three-phase uncontrolled diode rectifier bridge, dc/dc boost converter with MPPT controller, a dc bus with a capacitor and a current regulated PWM voltage source inverter. Perturb and Observe (P&O) technique is used for maximum power tracking. The performance of the developed model is studied for different wind speeds and load conditions. The wind power output is compared for the cases of with and without maximum power point tracking system. In this work the PQ control strategy is adopted for the inverter of the grid connected wind generation system. Simulation results show that the controllers can regulate the DC link voltage, active and reactive power produced by the wind based DG system.

Power Inverter Based Comparison of Torque Ripple Suppression in IPMSM with Concentrated Winding

This study compares the characteristics of a PWM voltage source inverter (VSI) and PWM current source inverter (CSI) for an IPMSM drive system with concentrated winding. Past analysis showed that the PWM CSI had inferior operating characteristics compared with the PWM VSI. Thus, high-performance PM motor drive systems have been using a VSI for small-capacity applications. There has been almost no research addressing improvements in CSI motor drive systems. In this study, experiments were performed to compare the three-phase current and torque characteristics generated by VSIs and CSIs.

Analysis of Peak-to-Peak Current Ripple Amplitude in Seven-Phase PWM Voltage Source Inverters

Multiphase systems are nowadays considered for various industrial applications. Numerous pulse width modulation (PWM) schemes for multiphase voltage source inverters with sinusoidal outputs have been developed, but no detailed analysis of the impact of these modulation schemes on the output peak-to-peak current ripple amplitude has been reported. Determination of current ripple in multiphase PWM voltage source inverters is important for both design and control purposes. This paper gives the complete analysis of the peak-to-peak current ripple distribution over a fundamental period for multiphase inverters, with particular reference to seven-phase VSIs. In particular, peak-to-peak current ripple amplitude is analytically determined as a function of the modulation index, and a simplified expression to get its maximum value is carried out. Although reference is made to the centered symmetrical PWM, being the most simple and effective solution to maximize the DC bus utilization, leading to a nearly-optimal modulation to minimize the RMS of the current ripple, the analysis can be readily extended to either discontinuous or asymmetrical modulations, both carrier-based and space vector PWM. A similar approach can be usefully applied to any phase number. The analytical developments for all different sub-cases are verified by numerical simulations.

Universal active and reactive power control of electronically interfaced distributed generation sources in virtual power plants operating in grid‐connected and islanding modes

The control paradigms of the distributed generation (DG) sources in the smart grid are realised by either utilising virtual power plant (VPP) or by employing MicroGrid structures. Both VPP and MicroGrid are presented with the problem of control of power flow between their comprising DG sources. This study depicts this issue for VPP and proposes a novel and improved universal active and reactive power flow controllers for three-phase pulse width modulated voltage source inverters (PWM-VSI) operating in the VPP environment. The proposed controller takes into account all cases of R–X relationship, thus allowing it to function in systems operating at high, medium (MV) and low-voltage (LV) levels. Also proposed control scheme for the first time in an inverter control takes into account the capacitance of the transmission line which is an important factor to accurately represent medium length transmission lines. This allows the proposed control scheme to be applied in VPP structures, where DG sources can operate at MV LV levels over a short/medium length transmission line. The authors also conducted small signal stability analysis of the proposed controller and compared it against the small signal study of the existing controllers.

Digital Non-linear Controller-based Active Power Filter for Harmonic Compensation

This paper presents a design and implementation of digital non-linear controller-based, three-phase shunt-active filter for power line conditioner system. The active power filter is implemented with PWM-Voltage Source Inverter and its switching pulses are generated from Space Vector Modulation techniques. The active filter is applied for power quality improvements by compensating harmonics in the distribution network due to non-linear loads. The harmonic components are extracted from the sensed load currents from proposed non-linear control strategy. A simple and efficient Phase Locked Loop is used to synchronize the angle of vector orientation, which cancels the effect of harmonics and notches in the distribution network. An inner and outer loop Pl-control is incorporated with non-linear method for harmonic current control and dc-bus voltage regulator. Additionally, pre-filter is inserted at the input of each current loop in order to compensate for the effect of the left hand zero in the closed loop transfer functions. The entire control method is validated through MATLAB and also coded in assembly language for digital hardware implementation. The digital control algorithm is evaluated through TMS320F240 Digital Signal Processor for 10 kVAR active filter system.

Analysis of PWM Strategy for Reduction of Conducted Electromagnetic Interference in an Adjustable-Speed AC Motor Drive

This paper presents various pulse width modulation (PWM) strategies capable of reducing conducted electromagnetic interference (EMI) generated in PWM voltage-source inverter systems. EMI problems caused by both conducted and radiated noise emissions have become a great concern in electrical/electronic systems. Thus, their effects are currently considerably taken into account in circuit design phase in order to restrict or reduce these severe problems. The proposed PWM strategy, which is one of different traditional and/or novel reduction techniques to solve such a problem, is chosen as an EMI reduction method and studied herein. The simulated results show that active vector PWM strategy seems to be a good alternative for inverter system. The impact of dead time of PWM signals is also investigated and discussed.

Simple speed sensorless DTC-SVM scheme for induction motor drives

Abstract The paper focuses on the development of a novel DSP based high performance speed sensorless control scheme for PWM voltage source inverter fed induction motor drives. Firstly, two generic torque and flux control methods the Field Oriented Control (FOC) and Direct Torque Control (DTC), are briefly described. For implementation the sensorless scheme DTC with Space Vector Modulation (DTCSVM) has been selected because it eliminates the disadvantages associated with the DTC while keeping the advantages of both FOC and DTC. Secondly, the simple flux vector observer allowing speed sensor elimination is given. The novelty of the presented system lays in combining the DTC-SVM structure with a simple observer for both torque/flux and speed sensorless control. Furthermore, the DTC-SVM structure which operates in speed sensorless and torque control mode is presented. Finally, the description of a 50 kW laboratory drive and experimental results illustrating properties of the system are given.

An MRAS-Based Diagnosis of Open-Circuit Fault in PWM Voltage-Source Inverters for PM Synchronous Motor Drive Systems

In this paper, a simple and low-cost open-circuit fault detection and identification method for a pulse-width modulated (PWM) voltage-source inverter (VSI) employing a permanent magnet synchronous motor is proposed. An open-circuit fault of a power switch in the PWM VSI changes the corresponding terminal voltage and introduces the voltage distortions to each phase voltage. The proposed open-circuit fault diagnosis method employs the model reference adaptive system techniques and requires no additional sensors or electrical devices to detect the fault condition and identify the faulty switch. The proposed method has the features of fast diagnosis time, simple structure, and being easily inserted to the existing control algorithms as a subroutine without major modifications. The simulations and experiments are carried out and the results show the effectiveness of the proposed method.

Digital non-linear controller-based active power filter for harmonic compensation

AbstractThis paper presents a design and implementation of digital non-linear controller-based, three-phase shunt-active filter for power line conditioner system. The active power filter is implemented with PWM-Voltage Source Inverter and its switching pulses are generated from Space Vector Modulation techniques. The active filter is applied for power quality improvements by compensating harmonics in the distribution network due to non-linear loads. The harmonic components are extracted from the sensed load currents from proposed non-linear control strategy. A simple and efficient Phase Locked Loop is used to synchronize the angle of vector orientation, which cancels the effect of harmonics and notches in the distribution network. An inner and outer loop Pl-control is incorporated with non-linear method for harmonic current control and dc-bus voltage regulator. Additionally, pre-filter is inserted at the input of each current loop in order to compensate for the effect of the left hand zero in the closed l...

Evaluation of Slot-Embedded Partial Electrostatic Shield for High-Frequency Bearing Current Mitigation in Inverter-Fed Induction Motors

In the last decade, the use of PWM voltage-source inverters to control three-phase squirrel-cage induction motors has increased significantly. Consequently, high-frequency current activity in the bearings of inverter-fed motors and/or of devices mechanically coupled to their shaft is presently a common issue, ultimately shortening the bearings lifetime. In fact, bearing failures occurrence in inverter-fed motors increased dramatically in the last few years. Recently, the effectiveness of insulation-based bearing current mitigation techniques (e.g., bearings with insulated rings or ceramic spheres) and/or motor shaft grounding with an electric contact brush has been fairly investigated. However, there are some alternative high-frequency common-mode bearing current mitigation techniques requiring further investigation. In this paper, a stator slot-embedded partial electrostatic shield to reduce the capacitive coupling between the stator windings and the rotor in inverter-fed motors is proposed, analyzed, and implemented, being experimentally demonstrated its practicability and effectiveness in attenuating the common-mode voltage between the rotor shaft and the frame/ground, contributing to the reduction of high-frequency common-mode bearing current activity.

Reactive Power Compensation in Inverter Interfaced Distributed Generation

The consumption of reactive power is stochastic in nature for the distribution system. This uncertain variation of the reactive power leads to 1) Variation of voltage at the point of common coupling(PCC) 2)Low power factor 3)low efficiency 4) improper utilization of distribution system and 5) loss of synchronism for a grid connected inverter based – distributed generation. Now a day’s distributed generation (DG) system uses current regulated PWM voltage-source inverters (VSI) for synchronizing the utility grid with DG source in order to ensure the grid stability. In this paper reactive power compensation based hysteresis controller and adaptive hysteresis controller is analyzed for inverter interfaced DG which can control the active and reactive power independently. The adaptive hysteresis controller can reduce the current harmonic at PCC considerably which ensures lower total harmonic distortion (THD). The performance indices include THD of the grid current, fast current tracking during steady state and transient conditions. The studied system is modeled and simulated in the MATLAB Simulink environment.

Anti-Windup PID Controller With Integral State Predictor for Variable-Speed Motor Drives

The windup phenomenon appears and results in performance degradation when the proportional-integral-derivative (PID) controller output is saturated. Integral windup is analyzed on the PI plane, and a new anti-windup PID controller is proposed to improve control performance of variable-speed motor drives and is experimentally applied to the speed control of a vector-controlled induction motor driven by a pulse width-modulated voltage source inverter. The steady-state value of the integral state is predicted while the PID controller output is saturated, and this value is utilized as an initial value of the integral state when the PID controller begins to operate in a linear range. Simulation and experiments result in more similar speed responses against load conditions and step reference change over conventional anti-windup schemes. Control performance, such as overshoot and settling time, is very similar to that determined by PID gain in the linear range.

A New Near Optimal Harmonics Elimination PWM Algorithm for AC Traction Drives

For AC traction system, it is necessary to develop voltage source inverters (VSI) which is compatible with existing types of signaling systems adopted by various railway operators. The varying harmonics incidents of conventional sinusoidal–type PWM VSI is not particularly suitable as it produces unwanted harmonics within the signaling frequency band. One well–known solution to ensure that the unwanted harmonics do not appear on the spectra is by using the harmonics elimination PWM (HEPWM) switching method. However, the application of HEPWM has been somewhat limited by the fact that the switching angles cannot be calculated online by a microprocessor–based waveform generator. This is due to the fact that the equations involved are non–linear and transcendental in nature. The paper presents an algorithm to calculate near optimal switching angles, which will permit a fast and efficient realization using a microprocessor. The method is based on quadratic approximation approach which is derived from the computed trajectories of angles. Key words: power electronics; inverter; pulse-width modulation (PWM); railway signalling; harmonics

Photovoltaic based dynamic voltage restorer with power saver capability using PI controller

In this paper, a photovoltaic (PV) based dynamic voltage restorer (DVR) is proposed to handle deep voltage sags, swells and outages on a low voltage residential distribution system. The PV based DVR can recover sags up to 10%, swells up to 190% of its nominal value. Otherwise, it will operate as an Uninterruptable Power Supply (UPS) when the utility grid fails to supply. It is also designed to reduce the usage of utility grid, which is generated from nuclear and thermal power stations. PV based DVR system is comprised of PV system with low and high power DC–DC boost converter, PWM voltage source inverter, series injection transformer and semiconductor switches. Simulation results proved the capability of the proposed DVR in mitigating the voltage sag, swell and outage in a low voltage distribution system.

High-power CSI-fed induction motor drive with optimal power distribution based control

In this article, a current source inverter (CSI) fed induction motor drive with an optimal power distribution control is proposed for high-power applications. The CSI-fed drive is configured with a six-step CSI along with a pulsewidth modulated voltage source inverter (PWM–VSI) and capacitors. Due to the PWM–VSI and the capacitor, sinusoidal motor currents and voltages with high quality as well as natural commutation of the six-step CSI can be obtained. Since this CSI-fed drive can deliver required output power through both the six-step CSI and PWM–VSI, this article shows that the kVA ratings of both the inverters can be reduced by proper real power distribution. The optimal power distribution under load requirements, based on power flow modelling of the CSI-fed drive, is proposed to not only minimise the PWM–VSI rating but also reduce the six-step CSI rating. The dc-link current control of the six-step CSI is developed to realise the optimal power distribution. Furthermore, a vector controlled drive for high-power induction motors is proposed based on the optimal power distribution. Experimental results verify the high-power CSI-fed drive with the optimal power distribution control.

New Topologies for Static Reactive Power Compensator Based on PWM AC Choppers

Nowadays, static reactive power control is widely used in electrical power networks. The former solution based on Thyristor Controlled Reactors is progressively replaced by PWM Voltage Source Inverters. The first solution is quite simple but requires bulky shunt passive filters whereas the second solution shows higher semiconductor losses and requires a significant cooling system. In this paper, the authors present new topologies which show a good compromise in comparison to the classical solutions. Single phase AC Choppers are used to achieve controlled impedances (capacitive or inductive) at the fundamental frequency and thus adjust the reactive power level. This concept is applied for medium or high power applications and multi-converter structures based on step down or step up AC choppers are proposed. An example of design concerning reactive power compensation in a 25 kV/50 Hz AC traction line is presented. Finally, experimental results obtained for a 1.2 MVAR prototype demonstrate the feasibility of these novel topologies.

Arc-suppression coil based on transformer with controlled load

In order to develop an arc-suppression coil (ASC) with rapid and continuous regulation and limited harmonic output in neutral resonant grounding power system, the ASC based on transformer with controlled load is proposed. The voltage source PWM inverter works as the secondary load of transformer, the reactance of the ASC can be regulated arbitrarily through controlling the inverter output current. Large capacity ASC can be realised by adopting the transformer with multiple secondary windings. An improved injecting variable-frequency signal method is adopted to detect the distribution network line-to-earth capacitance accurately. Three-phase dynamic simulation experiments have been carried out on the 800 kVA/10 kV prototype, the experimental results validate that the arc-suppression apparatus has the characteristic of high precision in capacitance detection, wide compensation range, fast response and few harmonics.

H? Observer Based Sensor-less Control Strategy for Interior Permanent Magnet Synchronous Motor

Nowadays a sensor-less vector control system for a motor drive becomes promising to avoid a position sensor. A back electro-motive-force or flux observer is used for sensor-less drive of permanent magnet synchronous motors from middle to high speed range. Thus, the estimation accuracy of the observer influences sensor-less drive performance. This paper proposes a sensor-less vector control system using the H? flux observer in which the observer gain is designed based on the H? control theory. This observer is insensitive to high frequency disturbances such as voltage disturbance due to non-linearity of PWM voltage source inverter, measurement noise of current sensors, and modeling errors. So, the total performance of a sensor-less control system is enhanced. The detailed configuration of the H? flux observer is described in this paper. Simulation results are compared with the conventional full-order flux observer-based sensor-less system.