Space Vector PWM Method Research Articles

Performance Analysis of Three-Phase Inverter Using Different Techniques for the Grid- Connected Pv System

The model of a three-phase voltage source inverter is examined based on space vector theory. SVPWM offers an improved outcome with the inverter as compared to the conservative SPWM technique for the inverter. There is a 15.5% upsurge in the line voltage of the inverter. SVPWM better exploits the available DC-link power with the SVPWM inverter. It has been revealed that the SVPWM method utilizes DC bus voltage extra competently and produces a smaller amount of harmonic distortion and easier digital realization in a three-phase voltage-source inverter. For converter‘s gating signals generation, the space-vector pulse width modulation (SVPWM) strategy lessens the switching losses by restricting the switching to two-thirds of the pulse duty cycle. A hypothetical study regarding the use of the SVPWM the three-level voltage inverter and simulation results are offered to prove the usefulness of the SVPWM in the involvement in the switching power losses lessening, output voltages with fewer harmonics. Nevertheless, despite all the above-cited benefits that SVPWM enjoys over SPWM, the SVPWM technique used in three-level inverters is more difficult on account of a large number of inverter switching states. The attained simulation outcomes were satisfactory. As prospects, future experimental works will authenticate the simulation results. A software simulation model is developed in Matlab/Simulink.

Flux-Trajectory-Optimization-Based Predictive Flux Control of Permanent Magnet Synchronous Machines

This article proposed a predictive flux control strategy for permanent magnet synchronous machines based on flux trajectory optimization. Instead of minimizing the instantaneous flux tracking error at the end of each sampling period, the effect of different control sets on flux trajectories within the entire sampling interval is taken into account in the cost function. As a result, steady-state torque and flux ripples can be suppressed. Besides, inaccurate sector determination found in the conventional predictive control strategies can be successfully avoided. As well as highly dynamic performances inheriting from the predictive characteristics, enhanced steady-state torque control performances can be guaranteed under different operating conditions. Although the extended control set is utilized to augment the control freedom and further reduce torque ripple, the control effect of the proposed algorithm does not rely on the increase of switching frequency. Compared with the traditional predictive control strategies based on either finite control set or an extended control set, a superior control effect can be obtained while keeping a low switching frequency. Moreover, duty cycle signals are directly obtained in the prediction process, and no additional space vector pulsewidth modulation method is needed. Experimental validations and comprehensive comparison are conducted to demonstrate the effectiveness of the proposed strategy.

A novel fast SVPWM method based on two-stage transformation for three-level inverter

Compared with the two-level inverter, the three-level inverter has excellent performance in pressure voltage switching loss and harmonic applied to the fields of the speed regulation and new energy generation. However, the computational complexity of the space vector pulse width modulation (SVPWM) method for multilevel inverter restricts the implementation on low cost microprocessor. This paper proposes a novel fast SVPWM method for three-level inverter to convert the space voltage vector in the three-level space to the two-level by vector subtraction with the central vector. The conduction time of each switch can be computed quickly so that the runtime is reduced significantly. Finally, the experimental results verify the effectiveness and practicability of the new space vector modulation algorithm based on two-stage transformation.

A SVPWM Method for Parallel Resonant DC Link Inverter With the Smallest Loss in the Auxiliary Commutation Circuit

In order to reduce the operating frequency and loss of the auxiliary commutation circuit (ACC) and current stress of auxiliary switches of a parallel resonant dc-link inverter (PRDCLI), this article proposes a novel space vector pulsewidth modulation (SVPWM) method. The novel SVPWM method can reduce the number of operations of the ACC to once in every PWM cycle on the premise of realizing soft switching of all switches, thereby reducing the operating frequency and loss of the ACC. At the same time, by adding the shunt dead time, the novel SVPWM method can avoid the superposition of the resonant current and load current, thereby minimizing the current stress of auxiliary switches. In addition, the novel SVPWM method can apply to any PRDCLI with the ability of variable zero voltage durations. Under the novel SVPWM method, according to the equivalent circuits of different operation modes, the operation principle, soft switching realization conditions and parameter design methods of the inverter are analyzed. Finally, a 10-kW/16-kHz prototype is built using insulated gate bipolar transistors to verify the validity of the novel SVPWM method.

Carrier-based PWM Method for Indirect Matrix Converters based on Space Vector Analysis

In this paper, a novel approach to realize the carrier-based pulse width modulation (CBPWM) method for indirect matrix converter (IMC) is presented. The advantage of the proposed CBPWM method is that only one triangular carrier signal with constant gradient falling and rising edges is used to generate the PWM to the power switches in both the rectifier and the inverter stages of IMC. The analysis of the proposed CBPWM method is based on the space vector approach and the relationship between CBPWM and space vector pulse width modulation (SVPWM) methods is provided. In this paper, four CBPWM methods called: sinusoidal PWM, third harmonic injection PWM, symmetrical PWM and discontinuous PWM are presented. These different CBPWM schemes are established according to the distribution of zero vectors and the switching pattern of the SVPWM method. The comparison of output voltage performance with different CBPWM schemes are investigated. Compared to the conventional method the calculation time of the proposed method is reduced around 50%. Concretely, the calculation time of the SVPWM method is 45 μs, while the calculation time of the proposed method is 22 μs. The experiments have been carried out to show the effectiveness of the proposed method.

DC Bus Current Sensed Space Vector Pulsewidth Modulation for Three-Phase Inverter

The dc bus current sampling technology with the traditional space vector pulsewidth modulation (SVPWM) scheme imposes several challenges, particularly at the low-modulation region and sector boundaries, where the duration of a nonzero vector may be so short that the phase current cannot be measured reliably. A new dc bus current sensed SVPWM (SSVPWM) method is proposed, in this article, to overcome shortcomings of the traditional algorithm. By introducing the concept of minimum sampling time, the unobservable area of the dc bus sampling system is divided accurately. Then, the SSVPWM and associated current reconstruction strategy are proposed by inserting the measurement vector and the compensation vector. Finally, experiments were performed on a 2.7-kW permanent magnet synchronous motor (PMSM), and the experimental results showed that the current sampling error of the proposed SSVPWM is less than 2% and the THD of three-phase current is less than 4.9%, which provides accurate current feedback for high-performance vector control.

A SVPWM Control Strategy for Capacitor Voltage Balancing of Flying Capacitor Based 4-Level NPC Inverter

A Space Vector Pulse Width Modulation (SVPWM) control strategy is implemented for capacitor voltage balancing of Flying Capacitor (FC) based 4-level Neutral Point Clamped (NPC) inverter. This flying capacitor based 4-level NPC inverter is developed for medium voltage and high power applications. This system includes 6 power switching devices, 2 clamping diodes and 2 flying capacitors per leg. The flying capacitors ensure to operate inverter normally and all the switching devices share the voltage stresses in identical manner. Also it controls the voltage across each capacitor and maintained at Vdc/3 times of applied dc voltage. The proposed SVPWM method takes advantage of utilizing redundancy switching states to control and balance the voltage across the capacitor using nearest switching state vector selection method. Moreover, this system provides reduced total harmonic distortion (THD), and minimized voltage stress. The control technique is implemented without using any look-up tables or effective logic tables or trigonometric functions. The simulation and experimental results of this proposed verified are verified using Matlab-simulink and FPGA controller respectively.

An efficient hybrid digital architecture for space vector PWM method for multilevel VSI

This paper presents an efficient, cost effective design implementation of a hybrid digital architecture for space vector pulse width modulation (SVPWM) method for multilevel inverters (MLIs). The SVPWM method is one of the most popular real time PWM method for three phase voltage source inverter (VSI). The implementation of SVPWM method becomes complex with an increase in the number of levels in a multilevel inverter. The SVPWM method for multilevel inverter is a multitask system. The main constraint when it comes to implementing SVPWM for multilevel inverters is the processing of dwell time computation and the generation of PWM gate signals for all of the switches with an accurate delay. A hybrid hardware structure consisting of a simple low-cost, low-power dsPIC micro controller (dsPIC 30F4011) and a state of the art Field Programmable Gate Array (FPGA) (Cyclone V 5CGXFC5C6F27C7N) is used to implement SVPWM. The proposed hybrid digital architecture utilizes the advantages and resources of the dsPIC and FPGA. The hybrid digital architecture meets the timing constraints of multitasking through synchronization and parallelism. A communication interface between the dsPIC and the FPGA reduces the design complexity. The software overhead for the communication interface remains fixed for any number of levels. The hybrid structure of the digital architecture provides scalability for the SVPWM method with more number of levels in multilevel inverter. The operation of the proposed hybrid digital architecture is experimentally validated with an optimized SVPWM method for a five level VSI. An optimized region identification algorithm and simple dwell time expressions are described for a five level SVPWM. The input DC of the five level VSI is obtained from a differential power processing (DPP) based PV system. Experimental results under different operating conditions are presented.

Design of New SVPWM Mechanism for Three-Level NPC ZSI via Line-Voltage Coordinate System

In this article, a novel space-vector pulsewidth modulation (SVPWM) mechanism is proposed for a three-level neutral-point clamped (NPC) Z-source inverter (ZSI) via the line-voltage coordinate system. In order to solve the problems of the adjustment of the complicated operational region and the complex computation of lookup tables in conventional methods, the newly designed SVPWM mechanism is developed from the basis of the vector synthesis. With this mechanism, switching vectors required to synthesize the reference vector can be easily identified, and the corresponding duty ratios can be directly obtained. According to the volt–second balanced principle and three operational modes of the three-level NPC ZSI, the up shoot-through status is inserted into the left side of the intersection point of the maximum phase modulation signal and the carrier wave signal. On the other hand, the down shoot-through status is inserted into the right side of the intersection point of the minimum phase modulation signal and the carrier wave signal. The effectiveness of the proposed SVPWM mechanism is verified by numerical simulations and experimental results. The salient features of the proposed SVPWM method are easiness in digital implementation, less computation time, and better power quality in comparison with traditional SVPWM schemes.

Equivalent Space Vector Output of Diode Clamped Multilevel Inverters Through Modulation Wave Decomposition Under Carrier-Based PWM Strategy

The carrier-based PWM method (CBPWM) and the space vector PWM method (SVPWM) are two main modulation methods for diode clamped multilevel converters, and there is a certain relationship between these two modulation strategies. For general 8 segments SVPWM modulation sequence in the multilevel inverter, the inherent relationship between these two modulation methods have been researched, but the relationship between CBPWM and SVPWM in an arbitrary level sequence has not been obtained. To solve this problem, an in-depth study of the relationship between the multilevel SVPWM method and the CBPWM method has been made in this paper. By decomposing the modulation wave, and the SVPWM can be achieved by multi-modulation waves CBPWM. And the relationship between SVPWM and CBPWM in N level with an arbitrary number of segments sequence are obtained. Thus, through simple multi-modulation waves CBPWM strategy, less THD in the spectrum and higher DC voltage utilization switching sequences of multilevel inverters can be obtained. The simulation and experimental results illustrate that the relationship between CBPWM and SVPMM is correct.

Control Strategy for Four-Leg Nine-Switch Inverter Under Unbalanced Loads

On account of that nine-switch inverter (NSI) cannot supply symmetrical voltages to unbalanced loads, based on the NSI, N-phase leg is added to the neutral points of the loads, which forms a four-leg nine-switch inverter (FLNSI). The neutral point voltages under unbalanced loads are analysed and derived by space vector pulse width modulation (SVPWM) strategy for calculating the duty ratio of N-phase leg. While the calculations of other three-phase legs duty ratios of SVPWM method remain unchanged. Although SVPWM method can realize FLNSI outputs symmetrical voltages for unbalanced loads, it needs trigonometric function calculation and sector judgements. The carrier-based pulse width modulation (CBPWM) strategy is proposed for the sake of simplifying SVPWM. All of the duty ratios are used to calculate modulation waves of FLNSI. Compare the modulation waves with a carrier, which can control the neutral point voltages as corresponding zero-sequence voltages. Therefore, two groups of three-phase symmetrical sinusoidal voltages are obtained under both balanced loads and unbalanced loads. Finally, the experimental results are given to show the advantages of FLNSI topology and to validate of the effectiveness of the applied modulation strategy.

A Fast Multilevel SVPWM Method Based on the Imaginary Coordinate With Direct Control of Redundant Vectors or Zero Sequence Components

This paper for the first time comprehensively presents a multilevel space vector pulse width modulation (SVPWM) method based on the imaginary coordinate system. This method is probably one of the most efficient methods in fast multilevel SVPWMs. It avoids trigonometric operation, look-up tables and only requires simple logic judgement and arithmetic calculation. A distinct advantage of this method over other coordinate-transformation-based methods is that it does not need to transform from the imaginary coordinate system back to the a-b-c (or α-β) coordinate in order to select the redundant vectors using look-up tables. The redundant vectors or zero-sequence components are directly worked out in the proposed method, e.g., for balancing dc-link capacitor voltages, which avoids identifying the starting vector, vector rotation direction (clockwise or anti-clockwise), vector sequence, etc. as used in conventional methods. This paper entails each step to implement this SVPWM method, which can be replicated for multilevel converters with any number of voltage levels. The presented method has been used and validated by various converters, including a three-level and a five-level neutral-point-clamped converter. The archive value of this paper is that it demonstrates a milestone of fast multilevel SVPWM based on coordinate transformation.

Unified SVPWM Algorithm and Optimization for Single-Phase Three-Level NPC Converters

The high-order harmonics caused by the modulation strategy can deteriorate power quality. The harmonic characteristics of the carrier-based pulsewidth modulation are relatively fixed and difficult to optimize, while space vector pulsewidth modulation (SVPWM) has more flexibility. The unified SVPWM design method for single-phase three-level neutral-point clamped (NPC) converters is fully presented in this article. Based on the proposed unified SVPWM method, two existing traditional vector sequences are designed first, and then several advanced multisegment SVPWM algorithms are proposed. According to the particularity of the three-level NPC topology, two hybrid SVPWM algorithms are proposed to optimize harmonic performance. Moreover, the high-order harmonic characteristics and the number of switching actions are analyzed in detail for all SVPWM algorithm modes. In addition, these SVPWM algorithms are associated and unified by introducing weight coefficients of the redundant vectors. Simulation and experimental results verify the feasibility and effectiveness of the proposed SVPWM algorithms, which show that the proposed methods can optimize high-order harmonic distribution and reduce the line current harmonics.

Tracking technique for the sudden change of PV inverter load

Many power electronics applications require a power calculation in the control system. To get a suitable output, engineers need to control the process and regulate the power exchange with the grid. Since real and reactive power calculations are so crucial a topic, a novel control strategy for a single-phase photovoltaic (PV) inverter has been developed. Therefore, Direct power control (DPC) and a single-phase three-level space vector pulse width modulation (SVPWM) combine as a control and modulation system. In this paper, predictive real and reactive power control and SVPWM method are conferred in the inner loop. A voltage controller based on a proportionalintegral (PI) scheme is used in the outer loop to acquire constant output voltage and provide power refers to the DPC. The performance of the proposed method is verified by using MATLAB/SIMULINK.

Carrier‐based PWM control strategy for Z ‐source two‐stage matrix converter

In the Z -source two-stage matrix converter (ZSTSMC), the unique shoot-through state of the Z -source network can increase the voltage transfer ratio. Its maximum value can reach 4.33. In order to solve the complexity of space vector pulse width modulation (SVPWM) for ZSTSMC, a carrier-based PWM (CBPWM) control strategy is proposed. The duty ratios of the rectifier stage and inverter stage are calculated by the SVPWM method. A carrier is constructed and combined with duty ratios to produce regular modulation waves of rectifier stage and inverter stage. Then, the inserted mode of the shoot-through state is optimised by analysing. The position of its insertion is adjusted so that the expressions of the shoot-through modulation wave is simple and regular. And the number of modulation waves is reduced from 5 to 4. Next, the modulation waves are compared with a carrier to obtain pulse signals which are used to produce driving signals through logic operation. The ZSTSMC is controlled by this strategy to obtain three-phase symmetrical sinusoidal input and output waveforms. The proposed method is identical in output to the SVPWM method. Finally, the experimental results are provided to verify the feasibility and validity of the proposed method.

Quasi-Z-Source Inverter using Space Vector Modulation and Sine PWM Method

This paper presents the performance comparison of sine PWM and SVPWM based quasi impedance source inverter (QZSI).QZSI are used to boost the DC link voltage and convert DC voltage into AC voltage in a single stage with a concentrated number of semiconducting devices. Space vector pulse width modulation (SVPWM) method is used to control the inverter output voltage and reduce the current harmonic. MPPT technique is also integrated into the SVPWM technique to improve the maximum output power obtained from PV cells. Shoot through concepts is used to increase the DC link voltage and reduce the separate requirement of the boost stage. The projected QSZI inverter is simulated using MATLAB simu-link. SPWM and SVPWM method are used to determine the circuit performance. The circuit performance is compared with simulation results.

Vector Weighting Approach and Vector Space Decoupling Transform in a Novel SVPWM Algorithm for Six-Phase Voltage Source Inverter

For six-phase permanent-magnet synchronous motor (PMSM) which has two sets of Y-connected three-phase windings spatially phase shifted by 30 electrical degrees, to increase the utilization ratio of the DC bus voltage, a novel space vector pulse width modulation (SVPWM) algorithm in full modulation range capability based on vector weighted method is proposed in this paper. The basic vector action time of SVPWM method is derived in detail, employing vector space decomposition transformation approach. Compared with the previous algorithm, this strategy is able to overcome the inherent shortcomings of the four-vector SVPWM, and it achieves smooth transitions from linear to overmodulation region. Simulation and experimental analyses demonstrate the effectiveness and feasibility of the proposed strategy.

Effect of center voltage vectors (CVVs) of three-level space plane on the performance of dual inverter fed open end winding induction motor drive

Dual inverter fed open end winding induction motor (IM) drive offers many advantages over other multilevel inverter fed IM drives. Pulse width modulation (PWM) techniques are employed for the control of output voltage and frequency. Space vector base PWM techniques are popular among all the PWM techniques. A simplified space vector PWM method with simple and small look-up table approach is presented for dual inverter configuration. Moreover the proposed space vector based PWM technique provides freedom in selecting the center voltage vector (CVV) by which different PWM techniques will be derived. The implementation of all these PWM techniques is generalized by using a constant a <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> . The derived PWM techniques show superior performance in reducing the zero sequence voltage (ZSV) by maintaining the same quality of output voltage. The performance of all these PWM techniques are evaluated theoretically and verified in real time through dSPACE 1104 control board.

PMSM Control using the 3DSVPWM to Decrease Motor Torque Ripple and Motor Current THD with a New Model

In this paper, a new model for a PMSM (permanent magnet synchronous motor) driver is proposed. The proposed model is envisioned as a better modulating drive current waveform. In the proposed system the modulating drive motor current waveform is more similar to ideal sinusoidal waveform. Advanced IGBTs and snubber circuits can be employed in the design of the driver to obtain high performance with a simultaneous reduction in THD (total harmonic distortion) and torque ripple of the motor. The proposed concept offers a significant decreasing for driver harmonics compared to classical SVPWM used. The inverter can be operated in 3-phase and 20 kHz switching frequency. A PMSM motor is operated at 3kW and 48V with the proposed model is evaluated via simulation with a corresponding SVPWM (space vector pulse width modulation) method. Results of torque ripple and THD of the motor currents on the model are discussed.

SVPWM Method for Multilevel Indirect Matrix Converter with Eliminate Common Mode Voltage

The multilevel indirect matrix converter (IMC) is a merit of power converter for feeding a three-phase load from three-phase power supply because it has several attractive features such as: Sinusoidal input/output currents, bidirectional power flow, long lifetime due to the absence of bulky electrolytic capacitors. As compared to the conventional IMC, the multilevel IMC provides high output performance by increasing the level of output voltage. In this paper, the novel approach topology of multilevel IMC by using the combination of the cascaded rectifier and the three-level T-Type inverter is introduced. Furthermore, the new space vector pulse width modulation (SVPWM) method for the presented multilevel IMC that eliminate the common-mode voltage is proposed in this paper. The simulation study is carried out in PSIM software to verify the proposed modulation method. Then, an experimental system is built using a three-phase RL load, a multilevel IMC, a DSP controller board and other elements to verify the effectiveness of the proposed modulation method. Some simulation and experimental results are illustrated to confirm the theory analysis.