Hybrid PWM Technique Research Articles

3-level inverter based compensator for power quality enhancement using proposed Trianguzoidal PWM technique

In today’s scenario, the integration of a grid-connected load system with a hybrid energy system (HES) is encouraged to improve the reliability of the system. With the stunning rise in nonlinear loads in HES over the last two decades, the power quality (PQ) of the system has emerged as a paramount concern in contemporary times. The power quality problems include the injection of harmonics in the source current, low input power factor, poor voltage regulation, the burden of reactive power, etc. So, to mitigate these power quality problems in a single-phase distribution system, a 3-level Cascade H-bridge (CHB) inverter-based shunt active power filter (SAPF) is employed alongside a proposed Trianguzoidal pulse width modulation (TRZ PWM) strategy. The single-phase distribution system with SAPF is simulated in fixed and dynamic load conditions to check the system’s efficacy. The proposed PWM techniques for SAPF are compared with conventional PWM techniques, i.e., level shift, phase shift, and hybrid PWM techniques. Results indicate satisfactory performance of the proposed PWM techniques, exhibiting low harmonic distortion in source current, well within IEEE 519 limits, and high active filtering efficiency (AFE) compared to conventional PWM methods. Furthermore, this paper provides detailed comparisons of conventional and proposed PWM techniques in the context of active & reactive power supplied or delivered by load, source, and compensator, input power factor, harmonics in source or grid current, AFE, and individual harmonic components concerning fundamental component of source current.

Dodecagonal Voltage Space Vector-Based Hybrid PWM Technique for the Reduction of Torque Ripple in OEWIM Drive

Dodecagonal Voltage Space Vector-Based Hybrid PWM Technique for the Reduction of Torque Ripple in OEWIM Drive

A Hybrid PWM Technique Employing Variable Switching Sequences for Current Ripple Suppression in Dual Three-Phase PMSMs

A Hybrid PWM Technique Employing Variable Switching Sequences for Current Ripple Suppression in Dual Three-Phase PMSMs

A Capacitor Voltage Balancing Hybrid PWM Technique to Improve the Performance of T-type NPC Inverters

A Capacitor Voltage Balancing Hybrid PWM Technique to Improve the Performance of T-type NPC Inverters

A Hybrid PWM Technique for SMES Integrated Solar PV Based Grid-Tied Transformerless Inverters

A Hybrid PWM Technique for SMES Integrated Solar PV Based Grid-Tied Transformerless Inverters

Modified hybrid PWM technique for cascaded MLI and cascaded MLI application for DTC drive

Multilevel inverter is increasingly utilised for DC/AC conversion in multiple electrical power applications due to its wide capabilities, low switching losses, and reduced output harmonics. Multilevel inverter faces some problems related to complex control, and high number of components. This paper presents a modified multilevel inverter topology that needs only three DC sources and eight switches to generate thirteen voltage levels. This high number of voltage levels enhances the multilevel inverter performance significantly. Also, this paper introduces a modified modulation technique to trigger the multilevel inverter switches. This modified technique is called Hybrid pulse width modulation. The modified multilevel inverter topology accompanied by the improved modulation methodology leads to a multilevel inverter of smaller size, simpler control, and staircase sinusoidal output waveform with noticeable reduction in the harmonics content without using any harmonics filter. Furthermore, the proposed multilevel inverter topology will be utilized along with a direct torque control (DTC) induction motor drive to emphasize its characteristics by improving the motor drive performance. Correspondingly, this research runs a comprehensive set of simulations to validate the features of these topology and modulation methodology through MATLAB/Simulink environment software.

Research of a Flexible Space-Vector-Based Hybrid PWM Transition Algorithm between SHEPWM and SHMPWM for Three-Level NPC Inverters

In this paper, one model of flexible space-vector-based hybrid pulse width modulation (HPWM) transition algorithm consisting of selective harmonic elimination pulse width modulation (SHEPWM) and selective harmonic mitigation pulse width modulation (SHMPWM) is applied and examined in a 10kV grid with a three-level neutral point clamped (3L-NPC) grid-connected inverter. These two modulation techniques are used to produce the appropriate firing pulses for 3L-NPC grid-connected inverters in different cases. SHMPWM is adopted to the grid-connected inverters to mitigate the required odd non-triplen harmonics according to the requirements of grid codes EN 50160 and CIGRE WG 36-05, while the firing pulses generated using SHEPWM is used to eliminate the primary low-order odd non-triplen harmonics completely. Meanwhile, one smooth and fast transition scheme is proposed by providing a suitable switching angles set at the transition point. Finally, it is demonstrated and validated by the MATLAB/SIMULINK model that smooth and quick transition is realized and there is no sudden change of current during the transition, as expected. Furthermore, this hybrid PWM technique is universal for different PWM methods based on the specific operating conditions.

Variable switching frequency hybrid PWM technique for switching loss reduction in a three-phase two-level voltage source inverter

Power loss reduction is one of the main objectives in power electronic system design for achieving higher efficiencies and enhancing system reliability. In this regard, this paper aims to develop a variable switching frequency hybrid pulse width modulation (VSF-HPWM) method to maximize loss saving while maintaining the same current total harmonic distortion (THD) of the conventional scheme. In doing so, this technique utilizes the modulation signal and the switching frequency simultaneously. Using a predefined mathematical representation of current ripple in every switching cycle, the modulating signal (either discontinuous or conventional space vector modulation) with lower RMS current ripple is applied. Meanwhile, the number of commutations under the constrains of constant RMS ripple is reduced by varying the switching frequency. The performance analysis is validated through MATLAB Simulink which shows that the proposed strategy can save up to 53% of switching losses with a similar THD of the conventional scheme.

A Predictive Hybrid Pulse-Width-Modulation Technique for Active-Front-End Rectifiers

Nowadays, active-front-end rectifiers are increasingly used as grid connected devices. Their efficiency and performances have become relevant for reducing the overall grid losses. This paper thus introduces a predictive hybrid pulse-width-modulation (PH-PWM) technique, adaptable to any space-vector PWM (SVPWM) controller. As opposed to hybrid PWM techniques based on sector partitioning, the PH-PWM technique selects the appropriate PWM sequence online with the help of a predictive algorithm. This selection is based on a cost-function where users can define a tradeoff between various criteria, such as the reduction of current distortion and switching losses, as presented in this paper. The use of the PH-PWM technique increases performances in comparison with the conventional PWM techniques. The simulation and experimental results are presented to confirm the effectiveness of the proposed PH-PWM technique. Aside from the tradeoff capacity of the proposed PH-PWM technique, the simulation results validate a reduction of the switching losses for the converter up to 23 $\%$ as compared with the conventional SVPWM technique.

Hybrid Pulse Width Modulation Strategy for Wide Speed Range in IPMSM with Low Cost Drives

The control performance of hybrid PWM inverter using a phase current measurement is presented in this paper. The hybrid PWM technique consists of space vector pulse width modulation (SVPWM) and six-step voltage control operation. The SVPWM is performed to reduce the harmonic components in the low speed region, and the six-step modulation is applied to increase the maximum speed of the IPMSM in the high speed region. Therefore, it is possible to obtain a great performance in both the low speed range and high speed range. However, the six-step modulation cannot be completely implemented, since the inverter that includes the lag-shunt sensing method has an immeasurable current region. In this paper, a quasi-six-step modulation using a modified voltage vector is proposed. The validity and usefulness of the proposed PWM technique is verified by MATLAB/Simulink and experimental results.