General Space Vector Modulation Research Articles

Enhanced deadbeat predictive current control with novel generalized space vector modulation for five‐level inverter fed permanent magnet synchronous motor drive with reduced torque ripples and less computational burden

SummaryTraditional electric drive control methodologies, such as field oriented control (FOC) and direct torque and flux control (DTFC), predominantly rely on multiple proportional‐integral (PI) controllers that demand complex tuning. While model predictive current control (MPCC) omits PI controllers, it has inherent challenges including high computational burden and tempered dynamics. Although two‐level inverters (2LI) are prevalent in many applications, their performance wanes in high‐power applications like high performance industrial drives and marine propulsions. Multilevel inverters (MLIs) are more efficient, but combined with space vector modulation (SVM), they add computational complexity, particularly at higher levels, limiting drive sampling frequencies and causing torque ripples and harmonics, affecting performance. To address the above drawbacks, this manuscript presents a deadbeat predictive current control of five‐level inverter fed permanent magnet synchronous motor (PMSM) drive with a novel generalized SVM algorithm with reduced computational burden and improved performance. The proposed method is validated through MATLAB/Simulink‐based simulation study and experimental implementation. The results are presented and discussed. The results are compared with DTFC and MPCC where it is observed that the proposed method offers superior performance with reduced computational burden and streamlined implementation.

Power Distribution Method for Single-Phase Cascaded Multilevel Converters Based on Space Vector Modulation

Cascaded H-bridge converters are interesting candidates for photovoltaic (PV) and energy storage systems, since PV panels and/or batteries can be directly connected to the input dc-side of each converter module. However, differences in the parameters of the batteries or variable ambient conditions may result in energy imbalances among the power modules. In these cases, conventional modulation strategies will lead to an increased distortion on the converter output voltage. Therefore, this paper proposes a generalized space vector modulation for single-phase cascaded H-bridge converters considering the power processed by each power module and maintaining a low-THD multilevel output voltage waveform. The proposed method improves the converter output voltage harmonic spectrum compared to the conventional phase-shifted modulation strategy in cases of power imbalance among modules. Experimental results are included to demonstrate the performance of the proposed method.

A Generalized Space Vector Modulation for Cascaded H-Bridge Inverters under Faulty Conditions

In this research, a new space vector modulation control algorithm is proposed to increase the reliability and the accuracy of the cascaded H-bridge multilevel inverters in case of faulty situations where one or several power cells do not function. When one or more switches of a cell are opened or shorted, that cell is considered faulty. By giving a detailed analysis on the impact of the faulty power cells on the voltage space vectors, the inapplicable voltage vectors are removed precisely. Consequently, the optimal redundant switching states are chosen such that the highest possible output voltage can be achieved. In addition, the balance of the three phases line-to-line voltage and current are maintained. The proposed algorithm is also generalized so that it can be applied to any level of H-bridge inverters. The validity of the method is verified by numerical simulations using MATLAB Simulink with an 11-level cascaded H-bridge inverter.

Model Predictive Control of PMSM Drives Based on General Discrete Space Vector Modulation

Apart from the basic voltage vectors of a inverter, virtual vectors can be generated by discrete space vector modulation (DSVM) technique. Thus, DSVM based-model predictive control (MPC) can achieve reduced torque ripples and current harmonics for a permanent magnet synchronous machine (PMSM) drive. However, the computational burden is also significantly increased due to a large number of candidate voltage vectors. In this article, a novel DSVM-based MPC is proposed, which can select the optimal voltage vector and calculate three-phase duty ratios in an efficient way without enumerating all the candidate voltage vectors, hence achieving good performance with low computational burden. The effectiveness of the proposed method is validated by the presented experimental results.

Generalized Space Vector Modulation for Ripple Current Reduction in Quasi-Z-Source Inverters

This article proposes a generalized space vector modulation (SVM) strategy for the three-phase quasi-Z-source inverter (qZSI), which can reduce the inductor current ripples by limiting the peaks in different sectors of the vector space. In the conventional ZSVM6 strategy, the shoot-through interval is divided into six equal parts, which is easy to implement. However, the inductor current ripples are not optimized. Generally, larger inductance is required to limit the current ripples, resulting in poor power density. By contrast, the proposed SVM strategy can minimize the current ripple, while maintaining the same total shoot-through time. Although the shoot-through intervals in the proposed SVM strategy are not identical, easy implementation still holds. The generalized strategy can ensure that the inductor current ripples are always smaller than the peak of the inductor discharging current ripple in a switching cycle. The proposed SVM strategy is derived in details and compared with the conventional ZSVM6 strategy. Simulations and experimental tests are presented to verify the effectiveness of the proposed modulation strategy for the inductor ripple current reduction.

Generalized Space Vector Modulation for Current Source Converter in Continuous and Discontinuous Current Modes

Three-phase current source converter tends to be attractive in future industrial applications. Therefore, the discontinuous dc-link current will occur if the current source converter operates in case of light load, which will distort the grid current. Many interesting solutions have been reported to deal with these problems. However, most of them are only valid in the discontinuous current mode (DCM) but not suitable in other conditions such as continuous current mode (CCM). With the different load conditions, there are two operational cases for the current source converter according to the different states of dc-link inductor current i L. Case 1: the inductor current $i_{L}$ is continuous. Case 2: the inductor current $i_{L}$ is discontinuous. To solve this problem, a generalized solution is proposed in this article, which is effective for both two cases. First, the operation principle of current source converter is analyzed and the disadvantages when the $i_{L}$ is discontinuous are revealed. Second, a new solution is proposed by using the new calculation method of duty cycles, where the current source converter can operate in both two cases. And then, the proposed solution is compared with the traditional one. The total harmonic distortion of grid current in traditional solution is 23.34%. However, it is reduced to 3.90% with the proposed solution. Finally, the proposed solution is carried out on the TMS320F28335 digital signal processor + XC3400 field-programmable gate array digital control hardware platform. The experimental results verify the effectiveness of the proposed solution.

Optimized Control of the Modular Multilevel Converter Based on Space Vector Modulation

This paper presents a general space vector modulation (SVM) method for the modular multilevel converter (MMC). Compared with earlier modulation methods, the proposed SVM method not only utilizes the maximum level number (i.e., $2n+ 1$ , where $n$ is the number of submodules in the upper or lower arm of each phase) of output phase voltages, but also leads to an optimized control performance in terms of capacitor voltage balancing, circulating current suppression, and common-mode voltage reduction. The maximum level number is achieved by introducing a new equivalent circuit of the MMC, and the optimized control is obtained by selecting the optimal redundant switching states. Since the computational burden of the SVM scheme is independent of the voltage level number, the proposed method is well suited to the MMC with any number of submodules. Simulation and experimental results are presented to validate the proposed method.

三相n レベルインバータに適用可能な一般的なスイッチング損失の低減法

A multi-level inverter has advantages in high blocking voltages and reduced harmonics. However, it needs more complex technical challenges in the utilization of redundant switching vectors as its level is increased.This paper proposes a general space-vector (SV) modulation method for the optimal reduction of the switching losses in three-phase PWM inverter of an arbitrary n-level type. The proposed method consists of two steps. One is the general principle for generation of the SV map for an arbitrary n-level type. The other is the optimal selection of the SV pattern which minimizes the switching losses considering the three-phase currents based on the two-phase modulation method. Simulated examples controlled according to the proposed method are shown for some different levels.

Applying Reduced General Direct Space Vector Modulation Approach of AC–AC Matrix Converter Theory to Achieve Direct Power Factor Controlled Three-Phase AC–DC Matrix Rectifier

This paper presents a novel approach to achieve both tight dc voltage regulation and direct power factor control by applying general direct space vector modulation (G-SVM) of matrix converter theory to a three-phase ac–dc matrix rectifier. The reduced form of G-SVM and the derivation of the three-phase ac–dc matrix rectifier from a three-phase ac–ac matrix converter are described and theoretically justified. The proposed matrix converter features intrinsic buck conversion, tight output voltage regulation via modulation, inherent capability of four-quadrant operation, elimination of the bulky storage component on the dc bus, and sinusoidal input current. Moreover, the reduced G-SVM-controlled three-phase ac–dc matrix rectifier can achieve leading, lagging, or unity input power factor by simple and direct control of the input current displacement angle. This significantly benefits the potential application of the reduced G-SVM-controlled three-phase matrix rectifier to automotive, aircraft, ship, and other three-phase standby dc supplies. In these applications, the unity power factor control is indispensable when the dc load widely changes. Simulated and experimental verification for this strategy has been presented and discussed in this paper.

SVM Procedure for $n$-Phase VSI With Low Harmonic Distortion in the Overmodulation Region

Space vector modulation (SVM) technique has become a standard method for the impression of voltage references in conventional three-phase voltage source inverters. The method is nowadays used in multiphase (more than three) drives, where linear and overmodulation regions are covered only for the five-phase case. This work proposes a general SVM procedure for linear and overmodulation regions in <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$n$</tex></formula> -phase drives (being <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$n$</tex></formula> any odd number, <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$n &gt; 3$</tex></formula> ) and simplifies the extension of SVM to the multiphase case. The proposed method achieves the reference voltage at the fundamental frequency while reducing introduced harmonic components in the overmodulation region compared to previous proposals.

Non-Sinusoidal SVPWM for Five-Phase Inverter Based on MMF Equivalence

The multi-phase inverter modulation and control method is a hotspot of multiphase systems. There is no general space vector modulation available due to the inherent difficulty in synthesizing more than one independent space vector simultaneously in different d-p planes. This paper established the distribution model of five-phase inverter space vector from a novel perspective of magnetic motive force (MMF) equivalence. And then a multi-dimensional SVPMW method applicable to the non-sinusoidal voltage output was proposed based on the obtained space vector distribution laws. The proposed multi-dimensional SVPWM method effectively improves the fundamental modulation range and is suitable for five-phase inverter non-sinusoidal modulation.

Generalized Algorithm for Pulse Width Modulation Using a Two-Vectors Based Technique

This paper presents a generalized and compact space vector modulation algorithm valid for both (a, b, c) and (x, y) coordinates, suitable for triangle comparison modulators. The proposed algorithm uses a two base-vectors duty cycle computation by mapping the solution space into only three parallelogram shaped zones (Fig. A). This generalized algorithm is especially suited for vector control applications requiring high dynamic response and for applications where changes in demand may happen at a frequency comparable with the modulator’s carrier frequency. Several carrier base modulation methods extensively described in the literature are obtained from the proposed generalized space vector modulation algorithm with the introduction of the null vector ratio δ. The proposed method has been experimentally tested, and a practical implementation of the generalized algorithm with low computational requirements is presented.

A New Generalized Space Vector Modulation Algorithm for Neutral-point-clamped Multilevel Converters

Neutral-point-clamped converters are increasingly applied in industrial drive systems as they allow the use of lower voltage devices in higher voltage applications, provide reduced output voltage total harmonic distortion(THD), and can develop low common mode voltage. Several distinct modulation strategies have been proposed in the past for eliminating the common mode voltage, providing low THD output voltage or reducing the neutral point current ripple. However each of these strategies improves the performance of the converter in one view point while losing performance in the other view point. A new generalized space vector modulation technique is proposed. Analytical model and simulation results are presented.