Four-Dimensional 24-Sector SVPWM Techniques for Split-Phase Induction Motor Drives: Analysis of Modulation Process and Efficient Implementation

This paper presents a modified space vector pulse width modulation (MSVPWM) technique for nine-level cascaded H-bridge (CHB) inverter. Based on a modular structure and absence of capacitor balancing problems, CHB inverter topology is preferred. Nowadays, space vector PWM (SVPWM) control scheme has achieved higher attention among different PWM techniques. In general, SVPWM method is realized based on disintegrating higher-level hexagons into a number of two-level hexagons. Compared to conventional SVPWM technique, the proposed MSVPWM technique reduces the computational burden and memory requirement involved in the realization of nine-level SVPWM. This is achieved by reducing the number of two-level hexagons without losing the inverter output voltage profile. Also a further modified space vector pulse width modulation technique is presented, which greatly reduces the computation efforts. The proposed SVPWM techniques are applied to a nine-level CHB inverter by using MATLAB/SIMULINK software tool and are compared with carrier-based sinusoidal pulse width modulation (SPWM) technique to validate the proposed techniques. The proposed SVPWM schemes produce lower harmonic distortion and higher DC bus utilization compared to SPWM technique. To verify the practicality of the proposed SVPWM techniques, experimental results are presented on nine-level CHB inverter.

Due to its advantages, the asymmetrical dual three-phase induction motor drive is a strong choice in high-power applications. However, the common-mode voltage produced by the voltage source inverters affects the winding insulation and damages the bearings. Common-mode voltage is also responsible for electromagnetic interference and leakage currents. This paper, therefore, analyses the common-mode voltage produced by the inverter supplying a dual three-phase induction motor drive and proposes a novel modified space vector decomposition-based Space Vector Pulse Width Modulation (SVPWM) technique for common mode reduction. The vector space decomposition-based space vector modulation technique offers excellent flexibility as it reduces the common-mode voltage (CMV) by exploiting the additional degree of freedom in a dual three-phase system. The common-mode voltage (CMV) can be reduced to one-sixth of the DC link voltage compared to the highest CMV, i.e. half of the DC-link voltage produced in conventional space vector modulation. The proposed method is also validated experimentally to demonstrate the effectiveness of the proposed scheme in terms of the amplitude of CMV, pulsations, and total harmonic distortion(THD) in current.

This article proposes a modulating and carrier-based dodecagonal space vector pulse width modulation (DSV-PWM) technique for split-phase open-end induction motor (OEIM). The advantage of the DSV-PWM technique is that the fifth and seventh order (6n±1; n=1,3,5,...) harmonics are eliminated from the phase voltage of the split-phase OEIM. The modulating waveform is generated from the sinusoidal reference signals by adding the triplen, and fifth and seventh order harmonics. This modified reference waveform is compared to the triangular carrier waveform to generate the PWM gating signals for inverter-1 so that the vector addition from two inverters results in a 12-sided polygonal space vector structure for the PWM control. The PWM signals for the two-level inverter-2 connected to the other end of the OEIM are produced by performing a small logical operation using the PWM signals of inverter-1. The dc voltage relation between inverter-1 and inverter-2 is 1:0.366. The timing duration for inverter-1 and inverter-2 is the same to generate the dodecagonal space vector structure (DSVS) and can be easily implemented as in the case of a conventional sine-triangle PWM technique in a three-phase drive. So, mapping the space vectors of the DSVS of conventional split-phase to that of the OEIM drive is simple. This can be achieved using a logical operator like <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xor</small>. Thus, the computation burden of the digital signal processors to produce the DSV-PWM signals is reduced with the proposed algorithm which is 3.45 times than the conventional space vector-based implementation using sector identification, vector time computation, and storing the switching vectors. A detailed analysis of the modulating waveform and DSV-PWM signal generation with the experimental verification of the proposed drive is presented in this article.

A review of the sinusoidal pulse-width-modulation (SPWM) and the space vector PWM (SVPWM) techniques for AC motor drives is reported, taking into account secondary effects such as the digital quantization, the dead time, and the dwell time. Simulation results show close agreement with the measured harmonics caused by an experimental digital-signal-processor (DSP)-controlled inverter operating in the same conditions. The SPWM waveforms have cleaner spectra than the SVPWM, but the quality factors are higher with respect to the SVPWM, having the same peak value of the voltage reference. As a consequence, if the switching frequency is high enough, the losses due to the harmonics can be almost neglected, and the SVPWM seems to be the best solution in terms of output voltage, harmonic losses, and number of switchings per cycle.

The space vector pulsewidth modulation (SVPWM) techniques enhance the performance of multilevel multiphase inverters. With multilevel (three-phase) inverters and with (two-level) multiphase inverters, it is widely accepted that the typical SVPWM strategies have an equivalent carrier-based pulsewidth modulation (CBPWM) counterpart, which produces identical results. However, the conclusions reached in the articles that show these cannot be applied, nor even extended, to SVPWM techniques with more than two levels and three phases. This article shows that the most widely accepted multilevel multiphase SVPWM techniques have a fully equivalent CBPWM counterpart, which consists of a phase disposition pulsewidth modulation with an appropriate zero-sequence injection scheme. Closed-form expressions to calculate the zero sequences are provided. The proposed modulation techniques are simulated and then implemented in a field-programmable gate array, showing that the equivalent CBPWM techniques produce identical results as the original SVPWM ones, but with a significant reduction of hardware requirements. The proposed methodology can be generalized to other multilevel multiphase SVPWM techniques.

PWM inverters used in motor drives produce high frequency Common Mode Voltages (CMV) which results in Common Mode (CM) currents and bearing currents due to parasitic capacitances. These currents cause abominable effects in electronics devices and develop voltage at motor shaft. When voltage exceeds dielectric breakdown voltage of lubricant film, it develops a huge bearing current which can damage bearings in very short interval. This paper emphasis on mitigation of CM currents and bearing currents by minimizing CMV produced by inverter-motor system based on selection and refinement of PWM algorithm without any additional hardware change. Multilevel inverters are apt for industrial applications due to low voltage distortion and less stress on switching devices than conventional two level inverter. To Investigate the effects on CMV, CM currents, bearing currents and motor shaft voltage, a high frequency Induction Motor (IM) model was chosen and analysis was done with different PWM techniques. The present work focused on three level Diode Clamped MultiLevel Inverter (DCMLI) and proposed new Space vector Pulse width Modulation (SVPWM) by choosing reductant CMV vectors in combination with sequence of changing one state in phase during switching transition. The proposed SVPWM technique shows the effectiness to reduce CMV as well as Electro-Magnetic Interference (EMI) and validated using MATLAB simulations.

In an isolated mode operation of wind power generating system (WPGS), operating voltage and frequency are affected under sudden change of load because of more transient time, higher total harmonic distortion. To minimize the effects, the WEGS should be operated with suitable controller and the inverter should be operated with required pulse width modulation (PWM) technique. In this paper, the proposed WPGS is simulated using MATLAB/Simulink with adaptive voltage controller (AVC) and load current observer (LCO) and the inverter is operating with Unified voltage Space Vector PWM (USVPWM) technique to improve the transient behaviour of the system. The same proposed system is also simulated with conventional space vector pulse width modulation (SVPWM) techniques. The simulation results will be analyzed in various load conditions. The conventional SVPWM results compared with the USVPWM results like transient time, load voltage and load current total harmonic distortion under balanced three-phase load.

Currently open-end winding induction motors fed by a dual inverter (OEWIM-DI) present an innovative approach to enhance the performance of modern electric drive systems; such as electrical vehicles and electric aircraft applications. However, the dual inverter topology requires a proper switching control strategy to enable the OEWIM drive to fully achieve its performance. This work aims to investigate experimentally the impact of different Decoupled Discontinuous Pulse Width Modulation (DDPWM) control strategies on the performance of the OEWIM-DI supplied by a common DC-link. The criteria performance adopted in this study are: (i) the Total Harmonic Distortion (THD) of the current and voltage, (ii) the Zero Sequence Voltage (ZSV), (iii) the Common Mode Voltage (CMV), and (iv) the dual inverters losses. The various DDPWM control schemes for the 1.5 kW OEWIM-DI motor drive are implemented on a dSPACE 1104 board and the results are compared with the popular and widely used Space-Vector PWM (SVPWM) strategy. From the results, it can be concluded that the optimised DDPWM technique gives the best performance. This technique has reduced the CMV by one level and reduce the losses by 50% while having the same THD and ZSV obtained with the SVPWM technique.

the Simulation model of DDPMSG 10KW grid Connected are developed using MATLAB 2013(a) and FAST Simulator. In addition to it SVPWM technique has been applied for 10KW grid connected model. Space vector pulse width modulation has been used for obtaining the output voltage with less distortion. An interface has also been developed between FAST and SIMULINK with MATLAB, enabling users to implement advanced turbine controls in SIMULINK convenient block diagram . The FAST subroutines have been linked with a MATLAB standard gateway subroutine in order to Generator torque control, nacelle yaw control, and pitch control modules can be designed in the SIMULINK environment. The fully controlled converter has been used to provide separate control for active and reactive powers. The simulation results in MATLAB SIMULINK 2013a showing the model have good dynamic and static performance. Index Terms: Direct drive permanent magnet synchronous generator, space vector pulse width modulation, fully controlled converters. I. Introduction The aim of this research is to model an autonomous control wind turbine driven permanent magnetic synchronous generator.(PMSG) which feeds alternating current (AC) power to the utility grid. Furthermore, this research also demonstrates the effects and the efficiency of PMSG wind turbine which is integrated by autonomous controllers. In order for well autonomous control, two voltage source inverters are used to control wind turbine connecting with the grid. The generator-side inverter is used to adjust the Synchronous generator as well as separating the generator from the grid when necessary. The grid-side inverter controls the power flow between the direct current (DC) bus and the AC side. Both of them are oriented control by space vector pulse width modulation (SVPWM) with back-to-back frequency inverter. Moreover, the proportional-integral (PI) controller is enhanced to control both of the of the converters and the pitch angle of the wind turbine. II. Inverters And The Pitch Angle Of The Wind Turbine According to the continuous development of wind power technology, the efficiency of inverter device is facing some tough issues and plays a vital role in the improvement of wind power generation system performance. They need to be enhanced by controller (3) to improve the efficiency and the reliability. Inside them, MPPT integrating with the back to back space vector Pulse width modulation (4) is the advantage of controller (3), which is used to measure the rotor speed and compare with the calculated optimal rotor speed. On the other hand, not only does the inverter take an advantage in efficiency control but also the pitch angle controller takes another important part of wind turbine. It is integrated to adjust the aerodynamic torque of the wind turbine when this study rates wind speed

This paper aims at obtaining fixed output voltage of frequency 50 Hz to the load by a Self Excited Induction Generator (SEIG) employed in Wind Energy Conversion System (WECS). The output voltage of a SEIG is a function of wind turbine’s speed, which varies with wind velocity. Due to the variation in shaft speed of the wind turbine, the output voltage and frequency of Doubly Fed Induction Generator (DFIG) will vary. In this paper, a new WECS is proposed in which the conventional PWM AC/ DC/ AC converter is replaced by a Matrix Converter (MC) topology and the DFIG machine is replaced by a low cost Squirrel Cage Induction Generator. MC eliminates bulky DC link capacitor, provides bi-directional power flow capability, independent control on the output voltage magnitude, frequency and phase angle as well as the input power factor. Space Vector Pulse Width Modulation (SVPWM) technique is used for controlling MC in such a way that output load voltage and frequency is kept constant for all wind velocities. The SVPWM technique provides higher voltage transfer ratio without lower order harmonics. SVPWM is digitally implemented using DSP processor (TMS320 F2407A). Switching times are pre-calculated offline. Semi soft commutation procedure for safe switching control of MC switches is also presented.

In this paper, a comparative study of shunt active filter (SAPF) with Sinusoidal pulse width modulation (SPWM) and Space vector pulse width modulation (SVPWM) technique to mitigate source current harmonics which are producing by the nonlinear load. In conventional diode clamped multilevel inverter extra diodes and balancing circuit is required. In proposed H-bridge inverter reduction of complexity and cost. The performance of SPWM and SVPWM technique is analysed by using MATLAB/ Simulink software.

Inverters have many application areas including the variable frequency drives applications of the motor industry. Three-phase inverters based on the three-phase system that we are using are becoming more common. The implementation of the space vector PWM (SVPWM) modulation technique in three-phase inverters is more advantageous than other modulation techniques due to the lower harmonic content and higher DC bus utilization it provides. A delay time, also called the dead-time, is added to the rising edge of the PWM signals for triggering the gates of the switches to avoid shoot-through faults in the inverters. Although it has a protection advantage, it has some disadvantages such as output voltage drop, phase shift, zero current clamping and increase in total harmonic distortion (THD) of the output current. In this study, these effects of dead-time are compensated by employing the simple yet effective feedforward method using the SVPWM technique. Moreover, the relationship between the effects of the dead-time and switching frequency is investigated. The results exhibit that the THD of the current is optimized when the switching frequency is controlled rather than kept constant.

Common-mode voltage (CMV) generated by the inverter causes motor bearing failures in multiphase drives.On the other hand, presence of undesired z-component currents in six-phase induction machine (SPIM) leads to extra current losses and have to be considered in pulse width modulation (PWM) techniques. In this paper, it is shown that the presence of z-component currents and CMV in six phase drive system are two major limiting factors in space vector selection. The calculated voltage space vectors for both symmetrical and asymmetrical SPIM drive system with three-level inverter are illustrated in the decoupled subspaces and described in terms of undesirable voltage components and CMV value. Several space vector pulse width modulation (SVPWM) techniques are investigated based on CMV and z-component currents generation. Then, a modified SVPWM technique with minimum current distortion, undesired current components and CMV with a modest torque ripple is proposed based on the simulation results.

An asymmetrical six-phase machine (ASPM) with two isolated neutral points is analyzed in two orthogonal planes-one of these planes is associated with electromagnetic energy transfer. The energy-transferring plane of ASPM has two regions-linear and overmodulation (OVM). Unlike the linear region, the average voltage injected in the non-energy transferring plane of the OVM region is non-zero. The efficacy of carrier-based implementation of an equivalent space-vector PWM (SVPWM) technique to reduce the computational burden is well-known in three-phase inverter literature. Although carrier-based implementations of popular SVPWM techniques of ASPM are researched for the linear region, such carrier-based implementation doesn’t exist for the OVM region. Moreover, a direct extension of the carrier-based strategy in the linear region to the OVM region isn’t possible because it requires the calculation of non-zero voltages in the non-energy transferring plane. This paper presents a carrier-based implementation of one of the SVPWM techniques in the OVM region, resulting in minimum RMS harmonic voltage. The proposed technique is a natural extension of an important known PWM technique applied in the linear region. The proposed algorithm generalizes the duty signals in terms of maximum, middle, and minimum of three intermediate signals. These duty signals are then compared with two carrier signals to generate the required gating pulses. The proposed algorithm is validated through simulation and experiment on a hardware prototype at a maximum power of 4.5 kW.

This paper is to present a new space vector pulse width modulation (PWM) algorithm for four switch three phase inverter (FSTPI) fed induction motor under DC-link voltage imbalance. By using reasonable mathematical transform, space vector PWM (SVPWM) technique for FSTPI under DC-link voltage imbalance or ripples have been solved, which is based on the establishment of basic space vectors and modulation technique in similarity with six-switch three-phase inverters. This approach has a very important sense to solve hard problems for FSTPI under DC-link voltage imbalance, for example ensuring the required voltage for undermodulation mode and overmodulation mode 1 and 2, extended to six-step mode. Matlab/Simulink is used for the simulation of the proposed SVPWM algorithm for undermodulation, overmodulation mode 1 and 2. This SVPWM approach is also validated experimentally using DSP TMS320LF2407a in FSTPI-IM system.