Symmetrical Space Vector Modulation Research Articles

Multiple load operation of indirect matrix converter for different frequencies using symmetrical space vector modulation

AbstractThis study describes an indirect matrix converter (IMC) that uses symmetrical space vector pulse width modulation (SSVPWM) to feed two loads from a single DC link at a variable frequency. Output stage‐I is connected to the static load, while output stage‐II is connected to the PMSM for speed control. It is appropriate for drive systems with variable frequency, such as those seen in wind power generation and aviation. In recent years, significant studies on AC‐AC converters have been conducted due to the rising interest in electric cars and renewable energy. The performance of permanent magnet motors is better than that of other types of AC motors due to their superior performance and residual flux permanent magnets. Contrary to normal back‐to‐back power conversion systems, IMC does not necessitate the use of capacitors in the DC‐link, decoupled control between the two‐stages, a simple clamping circuit or zero current switching in the rectifier stage, allowing the system's volume to be reduced. It is investigated how well the two output stages of the proposed IMC perform. To illustrate the benefits of the suggested IMC design, an improved SSVPWM is employed, and MATLAB/SIMULINK‐based simulations were performed to validate the efficacy of the modulation mechanism. In addition, the real‐time implementation of the work was validated using a real‐time simulator, OPAL‐RT (OP4510).

A Constant Switching Frequency DTC for PMSM Using Low Switching Losses SVM–An Experimental Result

A Constant Switching Frequency Direct Torque Control (CSF-DTC) with low switching losses Space Vector modulation (SVM) for Permanent Magnet Synchronous Motor (PMSM) drive is proposed in this work. The CSF-DTC combines Field Oriented Control (FOC) and basic DTC advantages. Indeed, the proposed control strategy improves the basic DTC performances, which features low flux and torque ripples as well as a fixed switching frequency. The improved DTC ensures also a fast and robust flux and torque responses by using Integral and Proportional (IP) controllers which guaranteed a good disturbance rejection.On the other hand, a symmetrical SVM technique with low switching losses in the PWM inverter is used in order to generate the desired stator voltage vector needed to control the stator flux and the motor torque. Simulation and experimental results are presentedin this paper.These results demonstrate well the performance of the basic and proposed DTC and they show the effectiveness of the constant switching frequency direct torque control.

Space-Vector-Modulated Method for Boosting and Neutral Voltage Balancing in Z-Source Three-Level T-Type Inverter

In this paper, a new modulation method is proposed for a Z-source three-level T-type inverter (3LT <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> I). The Z-source 3LT <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> I combines the merits of the Z-source two-level inverter and the advantages of the Z-source neutral-point-clamped inverter. Although the previous literature has proved that the space vector modulation (SVM) technique for Z-source 3LT <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> I produces the desired voltage transfer gain with minimized switching loss, it cannot deal with the neutral-point (NP) potential balance issue. Therefore, an improved SVM method addressing this problem for Z-source 3LT <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> I is proposed. The method simplifies the space-vector diagram of a Z-source 3LT <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> I into that of a Z-source two level inverter. In order to obtain NP potential balance, the pattern of the conventional symmetric SVM is changed by properly adding or subtracting a percentage of the minimum gate-on time. The upper and lower shoot-through states can be inserted into the improved symmetric SVM, thus offering av few advantages, including boosting ability, NP potential balance, and low switching loss. The considerate stable NP voltage and the boosting gain have been experimentally proven by results from a prototype inverter.

Space vector modulation strategy for neutral‐point voltage balancing in three‐level inverter systems

This study proposes a space vector modulation (SVM) strategy to balance the neutral-point voltage of three-level inverter systems. The proposed method is implemented by combining conventional symmetric SVM with nearest three-vector (NTV) modulation. The conventional SVM is converted to NTV modulation by properly adding or subtracting a minimum gate-on time. In addition, using this method, the switching frequency is reduced and a decrease of switching loss would be yielded. The neutral-point voltage is balanced by the proposed SVM strategy without additional hardware or complex calculations. Simulation and experimental results are shown to verify the validity and feasibility of the proposed SVM strategy.