Space Voltage Vector Modulation Research Articles

A Inverter Dead-time Compensation Method Based on Phase current Polarity Determination and Voltage Partitioning

The introduction of the dead time of the inverter solves the straight-arm conduction problem of the upper and lower power devices of the inverter, but also leads to the deviation of the actual output voltage of the inverter from the given voltage. Dead time increases the harmonic components of phase voltage and phase current, which is also an important factor leading to motor torque ripple. In this paper, the mechanism of the deviation of phase voltage and phase current caused by the dead time of voltage space vector modulation is analyzed, and the effect of dead time on phase voltage and phase current harmonic components is studied. A simple and effective dead time compensation method based on phase voltage division and phase current polarity determination is proposed to directly compensate the dead time. This method can suppress the current harmonic and torque ripple in the running state of the motor, and can greatly simplify the calculation process of the traditional dead time compensation method. Through the system modeling and simulation, it is verified that the method can significantly improve the current waveform distortion, and has good practical value.

Improved Online Maximum-Torque-Per-Ampere Algorithm for Speed Controlled Interior Permanent Magnet Synchronous Machine

In order to improve the performance of interior permanent magnet synchronous machine (IPMSM) based on space voltage vector modulation schemes, this paper presents a highly accurate online method to find the proper maximum-torque-per-ampere (MTPA) angles. This algorithm fully considers the nonlinear characteristics of the d -axis inductance, q -axis inductance, and permanent magnetic flux together. Additionally, the influences of temperature are taken into account. In this paper, the proposed method injects a small virtual angle signal into the current angle mathematically to track the stator current reference angle that is close to real MTPA points. Moreover, following a theoretical analysis method, the error of the virtual signal injection method is analyzed. Then, based on the results of error analysis, this paper proposes a compensation strategy that can significantly reduce the current angle error between the tracking point and real MTPA point. At last, various experiments on an IPMSM test bench verify the proposed control technique and overall performance.

Application of Open-Circuit IGBT Faults Diagnostic Method in DTC-SVM Induction Motor Drive

In this paper a simple diagnostic method of a single IGBT open-circuit fault is presented, it is dedicated for three- phase two-level voltage-inverter-fed vector controlled induction motor drive systems. A failure diagnosis is based on a transient analysis of a reference voltage space vector in stationary coordinates, without additional sensors. The diagnostic algorithm ensures detection and localization of single IGBT failures in time shorter than one period of a stator current fundamental harmonic, without regard to a drive operation point. The presented scheme of the diagnostic system can be easily applicable in the electric drives that use voltage space vector modulation algorithms. The main achievement of the research, whose results have been presented in this paper, is an experimental validation of the analyzed IGBT faults diagnosis technique in the drive with the Direct Torque Control algorithm.

An Improved DTFC based Five Levels - NPC Inverter Fed Induction Motor for Torque Ripple Minimization

This paper presents a five level Neutral Point Clamped (NPC) inverter fed IM (Induction Motor) drive for variable speed application. In general the stator current is very highly affected by the harmonic components. It can be affecting the torque to produce high torque ripple in IM at maximum to low speed region. Since the drive performances are depends on mathematical model contains the parameters variations, noise, common mode voltage, flux variation and harmonic levels of the machine. Torque ripples and voltage saturations are the most significant problems in drive application. To overcome this problem the DTFC (direct torque and flux control) technique based five-level neutral-point-clamped (NPC-5L) approach is used. The proposed control scheme uses to stator current error as variable. Through the resistance estimated PI controller rules based the selection of voltage space vector modulation technique is optimized and motor performance level has been improved. The torque & speed are successfully controlled with less torque response. The results are compared and verified with conventional three phases VSI under different control technique by Matlab/Simulink.

Application of Open-Circuit IGBT Faults Diagnostic Method in DTC-SVM Induction Motor Drive

In this paper a simple diagnostic method of a single IGBT open-circuit fault is presented, it is dedicated for three- phase two-level voltage-inverter-fed vector controlled induction motor drive systems. A failure diagnosis is based on a transient analysis of a reference voltage space vector in stationary coordinates, without additional sensors. The diagnostic algorithm ensures detection and localization of single IGBT failures in time shorter than one period of a stator current fundamental harmonic, without regard to a drive operation point. The presented scheme of the diagnostic system can be easily applicable in the electric drives that use voltage space vector modulation algorithms. The main achievement of the research, whose results have been presented in this paper, is an experimental validation of the analyzed IGBT faults diagnosis technique in the drive with the Direct Torque Control algorithm.

Simulation of DC Regulated Power Supply by SVPWM Control

To make the voltage of and the power factor of AC side adjustable, according to the working principle of the three-phase voltage source PWM rectifier,establish the mathematical model of DC regulated power supply, introduce the space voltage vector modulation technology, and build its circuit model based on SVPWM control on the Matlab/Simulink software platform, The simulation results show that this control strategy is feasible.

A Novel Space Vector modulation Scheme and Direct Torque Control for Four-switch BLDCM Using Flux Observer

The main purpose of this paper is to describe a DTC (direct torque control) method for four-switch brushless dc motor (BLDCM) drive. In the method, a novel voltage space vector modulation scheme, an optimal switching table, and a flux observation method are proposed. Eight voltage vectors are summarized, which are selected to control BLDCM in SVPWM pattern, and an optimal switching table is proposed to improve the torque distortion caused by midpoint current of the split capacitors. Unlike conventional flux observers, this observer does not require speed adaptation and is not susceptible to speed estimation errors, especially, at low speed. Global asymptotic stability of the flux observer is guaranteed by the Lyapunov stability analysis. DC-offset effects are mitigated by introducing a PI component in the observer gains. This method alleviates the undesired current and torque distortion which is caused by uncontrollable phase. The correctness and feasibility of the method are proved by simulation and experimental results.

Research on the Control of Distributed Power Grid-Connected Inverter

Based on voltage space vector modulation, a distributed power grid-connected inverter (DPGCI) utilizing double loop control strategy is researched, the system is able to feedback power to grid with constant power and unity power factor. the static and dynamic performance is good. Firstly, a mathematical model of inverter system in two-phase synchronous rotating coordinate is built, based on this, a outer power loop and inner current loop control strategy is proposed, realizing the independent control of active and reactive power. Experimental results show the correctness and validity of the control strategy.

Line-to-line Voltage Space Vector Modulation for Neutral-point Clamped Multi-level Converter with DC-link Capacitor Voltage Balancing Using Redundant Vectors

This article presents space vector modulation of line-to-line voltage for the three-phase neutral-point clamped n-level converter with DC-link capacitor voltage balancing using redundant vectors. The developed modulation strategy is based on an equivalent matrix structure of the neutral-point clamped n-level converter. The relation between the 3 × (n – 1) switching functions of the matrix converter and gate signals of transistors of the neutral-point clamped n-level converter is given. A line-to-line space vector modulation strategy for a matrix inverter is used to obtain the switching function. For one switching function, there is more than one combination to produce each output voltage. Thus, redundancies of different switch configurations for generation of intermediate voltages are used to limit the deviation of capacitor voltages. The gate signals of the neutral-point clamped n-level converter can be calculated by inversing the modeling parts. Here, line-to-line voltage space vector modulation for a neutral-point clamped n-level converter is designed without using a Parks transform. Moreover, n × (n – 1) redundant vectors are used for DC bus voltage balancing. To highlight the performances of the developed modulation strategy, simulation results are given for five- and seven-level neutral-point clamped converters. Experimental results are given for a neutral-point clamped three-level converter.

Combined Discrete Space Voltage Vector with Direct Torque Control for Bearingless Brushless DC Motor and Closed-Loop Suspended Force Control

In order to improve the performance of bearingless brushless DC motor, a closed-loop suspended force controller combining the discrete space voltage vector modulation is applied and the direct torque control is presented in this paper. Firstly, we increase the number of the control vector to reduce the torque ripple. Then, the suspending equation is constructed which is spired by the direct torque control algorithm. As a result, the closed-loop suspended force controller is built. The simulated and experimental results evaluate the performance of the proposed method. The more advantage is that the proposed algorithm can achieve the fast torque response, reduce the torque ripple, and follow ideal stator flux track. Furthermore, the motor which implants the closed-loop suspended force controller cannot only obtain the dynamic response rapidly and displacement control accurately, but also has the characteristics of bearingless brushless DC motor (such as simple structure, high energy efficiency, small volume and low failure rate).

The Combine Discrete Space Voltage Vector modulation with Direct Torque Control of Brushless DC Motor

The Combine Discrete Space Voltage Vector modulation with Direct Torque Control of Brushless DC Motor

Cascaded two-level inverter-based multilevel static VAr compensator using 12-sided polygonal voltage space vector modulation

A static VAr compensation scheme using 12-sided polygonal voltage space vectors for high power application is proposed in this study. Using the polygonal voltage space vectors, the dc bus utilisation is increased in linear modulation region and total harmonic distortion (THD) is improved significantly in over modulation region. The power circuit topology consists of two standard two-level inverters, which are connected in cascade through an open-ended winding transformer. In order to obtain the polygonal voltage space vectors, the dc-link voltage of inverter 2 is maintained at 0.366 times the dc-link voltage of inverter 1. A simple control strategy to maintain the required dc-link voltage ratio as well as for reactive power compensation is proposed. To verify the proposed strategy, simulation is carried in MATLAB/SIMULINK. Simulation study is performed in linear, over modulation regions of the inverter and also with unbalanced network voltages. A laboratory prototype is designed and developed to validate the simulation results. Further, this scheme is compared with a sinusoidal pulse width modulation-based VAr compensation scheme using the same topology.

Research on Direct Torque Control of Induction Motor Based on TMS320LF2407A

Abstract The direct torque control of Induction Motor is one of the high performance control system, which was proposed after the vector control scheme. During the recent 20 years, It has been developed rapidly for its concise system scheme, excellent dynamic and static performances. DTC system directly controls the electromagnetic torque and stator flux, using the analyzing method of space vector and stator flux orientation. This paper establishes the mathematical model of direct torque control (DTC) system of induction motor, and direct torque control (DTC) scheme of induction motor based on TMS320LF2407A is introduced. The control scheme gets the switch control signal of inverter with the space voltage vector modulation technology. Finally the approach has been implemented on DSP in a 1.1 kW drive. The results show that the DTC with SVPWM has many merits such as simple realization, good running performance and high voltage utilization ratio.

A Novel Double Hysteresis Current Control Method For Active Power Filter

A novel current control method is proposed in this paper and it is applied in active power filter. The method combines voltage space vector modulation (SVM) with double hysteresis current control (DHCC) techniques. SVM technology is an effective way to rid the unnecessary switching action and improves the utilization of the direct current bus voltage. The outer loop hysteresis can ensure fast dynamic response and precision. The optimal voltage space vector is introduced to the inner loop hysteresis to decrease the switching frequency. Simulation experiments verify the proposed method.

Wind Power System Based on Multilevel Matrix Converter

A complete direct-driving wind power system consisting of wind turbine, permanent-magnet synchronous generator, multilevel matrix converter with voltage space vector modulation strategy is proposed in this paper. The simulation model is set up through Matlab/Simulink, and the results have verified the control strategy is feasible. Multilevel matrix converters are suitable for high- voltage application of wind power generation system, and it has laid a good basis for the real system development.

A servo system of AC motor based on voltage modulation fitting for FPGA and consideration of voltage saturation

AbstractThis paper proposes a space voltage vector modulation (SVM) method for a speed servo system to obtain a quick current response. The proposed SVM method shortens the control lag time of the conventional SVM inverter. In addition, this proposed method is easily implemented in hardware using an FPGA (Field Programmable Gate Array) because the proposed SVM equations are transformed into expressions that hardly need multiplication. By using the proposed SVM method, the servo system realizes quick and stable current control with wide bandwidth. Moreover, by using PI controllers considering the voltage saturation and the torque limiter to the speed servo system, the servo system carries out stable speed control on voltage saturation. Both the proposed SVM method and the PI controllers considering voltage saturation are applied to the speed servo system of a vector controlled induction motor. The effectiveness of both the proposed SVM method and the PI controllers considering voltage saturation is verified by the experimental results. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(1): 60–68, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20989

Torque Ripple Suppression in Flux-Switching PM Motor by Harmonic Current Injection Based on Voltage Space-Vector Modulation

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The flux-switching permanent-magnet (FSPM) machine is a relatively novel brushless machine having magnets and concentrated windings in the stator instead of rotor, which exhibits inherently sinusoidal back-EMF waveform and high torque capability. However, due to the high airgap flux density produced by magnets and the salient poles in both stator and rotor, the resultant torque ripple is relatively large, which is unfavorable for high performance drive system. In this paper, instead of conventional optimization on the machine itself, a new torque ripple suppression approach is proposed in which a series of specific harmonic currents are added into <formula formulatype="inline"> <tex Notation="TeX">$q$</tex></formula>-axis reference current, resulting in additional torque components to counteract the fundamental and second-order harmonic components of cogging torque. Both the simulation and experimental results confirm that the proposed approach can effectively suppress the torque ripple. It should be emphasized that this method is applicable to all PM machines having relatively large cogging torque. </para>

Current Mode Integrated Control Technique for Z-Source Inverter Fed Induction Motor Drives

This paper presents a current mode integrated control technique (CM-ICT) using a modified voltage space vector modulation (MSVM) for Z-source inverter (ZSI) fed induction motor drives. MSVM provides a better DC voltage boost in the dc-link, a wide range of AC output voltage controllability and a better line harmonic profile. In a voltage mode ICT (VM-ICT), the outer voltage feedback loop alone is designed and it enforces the desired line voltage to the motor drive. An integrated control technique (ICT), with an inner current feedback loop is proposed in this paper for the purpose of line current limiting and soft operation of the drive. The current command generated by the PI controller and limiter in the outer voltage feedback loop, is compared with the actual line current, and the error is processed through the PI controller and a limiter. This limiter ensures that, the voltage control signal to the Z-source inverter is constrained to a safe level. The rise and fall of the control signal voltage are made to be gradual, so as to protect the induction motor drive and the Z-source inverter from transients. The single stage controller arrangement of the proposed CM-ICT offers easier compensation. Analysis, Matlab/Simulink simulations, and experimental results have been presented to validate the proposed technique.

Mixed Modulation Method of PWM Inverter by Considering Acceleration Torque and Voltage Saturation for Speed Servo System

The speed servo system of an AC motor should always have a rapid and smooth response without current ripple. For this purpose, this paper proposes a new mixed modulation method of the PWM inverter by considering acceleration torque and voltage saturation. The rapid and robust speed servo system often has the high gain speed controller and the high gain current controller. In this case, this speed servo system often has the voltage saturation in the transient state. This paper discusses the amplitude and THD of output voltage on the condition of voltage saturation for each voltage modulation method of three phase inverter such as the carrier comparison inverter using the two phase modulation (2ph. M) and the space voltage vector modulation (SVM) inverter. The carrier comparison inverter using the 2ph. M has the large voltage with large harmonic current. The SVM inverter has the smooth voltage response with small harmonic current. The proposed method switches over the SVM and the 2ph. M methods properly by considering acceleration torque and voltage saturation. The experimental results confirm the effectiveness of the proposed mixed modulation method of the PWM inverter.

Space Vector Modulation Inverter Considering Acceleration Torque and Voltage Saturation for Speed Servo System

This paper proposes a speed servo system based on a space voltage vector modulation (SVM) inverter with the mixed voltage limitation method considering acceleration torque and voltage saturation for AC servo motor. The servo system realizes both a quick speed response and a small value of total harmonic distortion (THD) in steady state. The experimental results of surface permanent magnet synchronous motor drive confirm that the proposed method achieves the fine speed and current performance.