Cascaded H-bridge Research Articles

Single-Phase Multilevel Inverter Design with Low Voltage Stress and Optimized Control Model

The research explicitly examines the power control of a single-phase renewable energy sources battery energy storage system (RES-BESS)mixed-distributing network designed for domestic usage. The system utilizes a cascaded H-bridge (CHB) conversion architecture as its grid connection. The CHB uses a hierarchical power management design consisting of a single centralized regulator for the top layer and several dispersed regulators for the bottom layer. The higher stratum produces the reference signals that need to be monitored. Under optimal circumstances, the CHB should operate efficiently with all solar panels at their Maximum Power Point (MPP) and with an electrical factor of 1. However, several functional limitations prevent this from always being feasible, such as limits related to voltage and current, biased shadowing, and State of Charge (SOC) incompatibilities. Hence, a novel optimization technique is introduced to take into account these impacts directly and calculate a collection of reference parameters to be monitored. This approach aims to maximize the long-term viability of the structure while ensuring compliance with the given limitations. The optimization method in this structure incorporates many functional needs, prioritizing them based on the specific operating circumstances. The decentralized management layer utilizes traditional feedback-controlling methods to monitor the best referencing. Experimental findings are conducted to verify the best method under normal conditions for operation and evaluate the efficacy of the suggested CHB arrangement with the complete control technique.

Comparison between Cascaded H-Bridge and Neutral Point Clamped Topologies in Medium-Voltage Systems

Medium voltage motor drives (MVD) come in various topologies that allow designers to choose the best option for their application based on technical and economic considerations. The Neutral Point Clamped (NPC) and Cascade H-Bridge (CHB) are the most particular topologies that have come to the fore. CHB and NPC MVD's primary operating principles, switching stress, topological complexity, and harmonic distortion of the inverter output will be presented in this article, along with a brief review of suitable modules. Even though the number of parts in a cascaded inverter is lower than that of a neutral point-clamped inverter, it has been demonstrated that the stress on the switches in both types of inverters is the same and that the resulting output waveforms are nearly identical in terms of harmonic distortion. The neutral point clamped topology requires less secondary winding from the transformer, fewer voltage-balancing capacitors, the same quantity of switches, and extra clamping diodes. Benefits of NPC include high-power-density inverters, enhanced output quality, reduced number of components, reduced heat losses, increased efficiency, elimination of commonmode voltages and currents thanks to an isolation transformer, and a remote transformer that allows for a more adaptable footprint. Additionally, the NPC drive rectifier system (Transformer and diode H-bridges) has the advantage of more simplicity, ease of assembly, fewer connections, fewer space requirements, and an expensive isolation transformer. The MATLAB simulation for both topologies was carried out, with 3 phase motor 3.8kV, 150 KW motor parameters.

A Novel Leakage Current Attenuation Method for Nonisolated Odd-Module Cascade H-Bridge in Single-Phase PV System

A Novel Leakage Current Attenuation Method for Nonisolated Odd-Module Cascade H-Bridge in Single-Phase PV System

Lightweight shuffle–SimAM network-based open-circuit fault diagnosis of grid-connected cascaded H-bridge inverters

Lightweight shuffle–SimAM network-based open-circuit fault diagnosis of grid-connected cascaded H-bridge inverters

Novel Voltage Balance Strategy for a Cascade H-Bridge with a Wide Stable Operating Region and a Low Input Current THD

Novel Voltage Balance Strategy for a Cascade H-Bridge with a Wide Stable Operating Region and a Low Input Current THD

Evaluation of a multiphase cascaded H-bridge inverter for induction motor operation

Multi-phase systems are becoming more popular for applications requiring high power and precise motor control, even if single-phase AC power is still frequently utilized in households and some enterprises. While both systems have benefits over single-phase, there are trade-offs associated with each. Because of its balanced operation and effective power transfer, the three-phase (3-Φ) system is the most widely used multi-phase system. Nevertheless, different phase values can be investigated for particular applications where reducing torque ripple and harmonic content is essential. Using odd numbers of phases (such as 5-Φ) that are not multiples of three is one method. This design has the ability to reduce torque ripple by producing a more balanced magnetic field as compared with even-numbered phases. But adding more phases also makes the system design and control circuitry more complex. Systems with five phases (5-Φ) provide a compromise between performance and complexity. Applications such as electric ship propulsion, rocket satellites, and traction systems may benefit from their use. Nevertheless, choosing a multi-phase system necessitates carefully weighing the requirements unique to each application, taking into account elements like cost, power transmission, control complexity, and efficiency. The increasing popularity of electric vehicles and renewable energy technologies has led to the need for inverters in current electric applications. Conventional inverters provide square wave outputs, which cause the drive system to become noisy and cause harmonics. Multi-phase multilevel inverters can be used to enhance inverter functioning and produce an improved sinusoidal output. This study focuses on an induction motor drive powered by a five-phase multilevel cascaded H-Bridge inverter. With less torque and current ripples in the motor rotor, the power conversion harmonics are reduced and the switching components of the inverter are under less stress. However, in comparison to traditional inverters, it does require a greater number of legs. Because the switches needed for the cascaded H-Bridge inverter are less expensive in five-phase systems, they are favoured over higher phase orders. Furthermore, the suggested inverter removes 5th order harmonics, something that is not possible with traditional inverters. A five-phase induction motor appropriate for variable speed driving applications is also suggested by this research. Lastly, utilizing pulse width modulation (PWM) converters and an FPGA controller, an experimental study is carried out to assess the dynamic performance of the suggested induction motor drive. Particular attention is paid to the In-Phase Opposition Disposition (IPD) PWM technique.

Model predictive control for single-phase cascaded H-bridge photovoltaic inverter system considering common-mode voltage suppression

In this article, a model predictive control (MPC) with common-mode voltage (CMV) suppression is proposed for single-phase cascaded H-bridge (CHB) inverters, which can also simultaneously achieve control objectives of grid-connected current tracking, voltages balancing of different H-bridge submodules on the DC-side and switching frequency reduction. To suppress high-frequency components of the common-mode voltage without additional switching devices, the algorithm proposed designs the predicted and reference values of the CMV and incorporates them in the cost function. At the same time, the capacitor voltages balancing control is integrated in the calculation of the optimal modulation function of the H-bridge, which reduces the complexity of control effectively. Besides, switching times of the MOSFETs are compared in two cycles. The cost function is constructed to represent comprehensive effect of the control. Finally, an experiment is performed on the hardware-in-the-loop experimental platform. The experimental results show that the proposed algorithm can offer a better voltage THD and reduce the times of switch action by nearly half while maintaining high-precision current tracking and maximum power point of photovoltaic modules, which alleviate the potential electromagnetic interference and cabling problem.

Comparative Study of Multilevel Converters using DQ Current Control

This paper presents a comprehensive comparative analysis of different multilevel converter topologies, including 2-level, Neutral Point-Clamped (NPC), Cascaded H-Bridge (CHB), and T-Type converters using the DQ current control strategy. The study aims to evaluate the performance of these topologies concerning current Total Harmonic Distortion (THD) and ripple in the direct and quadrature components of the current. A mathematical model of the grid is presented to facilitate the simulation study. The DQ current control scheme is implemented to regulate the current in both the direct and quadrature axes. The simulations are conducted under various operating conditions to capture the converters’ performance across different load scenarios and modulation techniques. Results indicate significant variations in the performance metrics among the different converter topologies. The 2-level converter exhibits higher THD and ripple compared to the more complex multilevel topologies.

Real-time harmonics optimization of seven level converter for megawatt scale solar PV-utility integration

This paper presents a new single photovoltaic (PV) array fed cascaded H bridge (CHB) submodule based three-phase 10 MW solar photovoltaic (SPV) plant for medium voltage utility applications. Each submodule comprises of a single PV array, cascaded H bridge cells and line frequency transformers. A 10 MW seven level converter based solar PV plant is realised with four submodules feeding solar PV array power to 33 kV grid. In megawatt scale multilevel converters based configuration, semiconductor switches experience reduction in voltage stress and requirement of high switching frequency for gating for switches is eliminated. Moreover, an efficient single stage MPPT based decoupled controller is implemented with genetic algorithm inspired fundamental frequency switching. GA based optimization technique is used to calculate optimal switching angles in offline mode. Obtained switching angles are incorporated to achieve closed loop optimized decoupled control of SPV system. Lower order harmonics are eliminated and power is fed to grid at enhanced power quality. This large scale PV system is modelled in MATLAB-Simulink and simulated results are validated in real time.

Research on Boost-Type Cascaded H-Bridge Inverter and Its Power Control in Photovoltaic Power Generation System

Research on Boost-Type Cascaded H-Bridge Inverter and Its Power Control in Photovoltaic Power Generation System

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.

A Simplified single-phase neutral-clamped H-bridge cascade converter FCS-MPC control

A Simplified single-phase neutral-clamped H-bridge cascade converter FCS-MPC control

CHBMLI based DSTATCOM for power quality improvemt in a three-phase three-wire distribution system with PI controller

This paper presents a cascaded h-bridge (CHB) multilevel inverter (MLI) based MLI based distribution static synchronous compensator (DSTATCOM). The main objective of this paper is to reduce source current harmonics in the distribution system by using a cascade H-bridge multilevel inverter (CHBMLI) as DSTATCOM with a proportional-integral (PI) controller. The PI controller compensates reactive power, reduces source current harmonics, and maintains the unity power factor in the distribution system. The conventional two-level inverter-based DSTATCOM has many disadvantages such as high total harmonic distortion (THD), and high switching stress power semi-conductor devices, suitable for only low-power applications. This paper to overcome these drawbacks by using MLI-based DSTATCOM. The proposed system simulations are verified in MATLAB/Simulink software. The verified results are source current, load current, and compensating current.

A novel jittered‐carrier phase‐shifted sine pulse width modulation for cascaded H‐bridge converter

AbstractCarrier phase‐shifted sine pulse width modulation is a common modulation strategy for medium‐ and low‐voltage cascaded H‐bridges (CHB). This paper proposes a novel jittered‐carrier phase‐shifted sine pulse width modulation (JCPS‐SPWM) to reduce the total harmonic distortion (THD) of the converter. It makes the carrier jitter regularly while the total switching times remain unchanged, which reduces the THD of the bridge arm voltage and current by moving the low‐order output harmonics of the bridge arm voltage and current to filterable high‐order harmonics. Since the total number of switching times remains unchanged, this modulation strategy will not cause any increase in switching loss. A seven‐level CHB simulation model and an experimental prototype are built to verify the effectiveness of the approach. The results show that harmonic content can be reduced by 47.5% compared with the traditional method, thus verifying the effectiveness of the JCPS‐SPWM.

Solar PV based seventeen level reduced switch symmetrical multilevel inverter topology fed induction motor

Multilevel inverters have received a lot of interest in recent years due to their ability to deliver more voltage levels than typical two-level inverters. Because of this property, multilevel inverters can produce output waveforms that closely resemble sinusoidal waveforms, lowering harmonic distortion dramatically. The emergence of reduced switch symmetrical multilevel inverter topologies has developed the curiosity of many different power conversion systems. These new topologies offer numerous advantages, including greater output voltage quality, fewer harmonic distortions, and increased power conversion efficiency. The inclusion of these inverters in the feeding of induction motors is one of their many prominent uses. A 17 levels of multi-level inverter (MLI) topology is presented with reduced switch count and harmonic reduction for power quality improvement. The inverter is fed by isolated equal photovoltaic panels which act as direct current or DC source. To reduce complexity, switching pulses are generated using hybrid pulse width modulation technique which is designed as controller. Through the use of MATLAB/Simulink, the performance assessment of a unique cascaded multilevel inverter-based reduced switch symmetrical inverter feeding an induction motor drive has been verified. The harmonic distortion with reduced switches obtained is 7.47% which is comparatively less than when compared with conventional cascaded H-bridge topology.

Comprehensive Analysis of DC Link Capacitors Used in Cascaded H-Bridge Motor Driver

An essential part of inverter design is selecting direct current-Link Capacitors (DCLC) for Medium-Voltage Cascaded H-bridge motor Drivers (MV-CHBMD). This article analyzes capacitor configuration for MV-CHBMD to improve the quality of driver output and input current depending on an analysis of DCLC current effects. The techniques were employed with two-level converters to find the harmonics, and the root mean square (RMS) value of the capacitor current has been expanded to seven-level MV-CHBMD. Additionally, a novel mathematical technique has been recommended for determining the RMS current and voltage ripple of the DCLC. The proposed MATLAB simulation technique provides a comprehensive analysis of the outcome results. This allows for easy customization to other modulation methods and application to higher-level MV-CHBMD. Specifically, it calculates the worst-case scenario for the DC-link voltage in a 1000-horsepower and 3.3-kV system. The study also presents empirical evidence that specific system components endure excessive stress. This information is valuable for accurately specifying system components and ensuring optimal system design in the MV-CHBMD system. This article examines the potential impact of standard mode voltage on the bearings of medium-voltage motors. In addition, an optimal approach for selecting DCLCs in a multilevel cascaded H-bridge (CHB) motor driver strategy is proposed, effectively eliminating voltage stress on switching devices. The effectiveness of these systems is demonstrated by presenting simulation results. A comprehensive study analyzed the performance of various inverter levels, including total harmonic distortion (THD) and efficiency. The DC link was constructed using the MATLAB platform to conduct a thorough analysis. The proposed approach exhibits superior performance and lower costs compared to traditional methods. The experimental work and test confirm the simulation results. The test result showed that selecting DCLCs in a CHB provides a higher-quality output waveform into CHB, which supports the controlling structure and reduces the probability of malfunctions.

Voltage balancing for active power filter using dual-frequency multicarrier modulation with balanced H-bridge control

In this paper, a switching control method integrated with voltage balancing feature is presented to manage operation of single-phase 5-level cascaded H-bridge (CHB) inverter as parallel-connected active power filter (PAPF), and at the same time maintain its voltage balance. CHB inverters are always preferred for PAPF due to their dominating features of modularity, flexibility and least components count. However, inherent voltage unbalance issues of CHB inverter which is due particularly to unequal switching operation across its individual H-bridge module have always been the most troublesome when handling CHB inverter. For consistent voltage balance across each H-bridge module, proportional-integral (PI) controller for voltage balancing control and multicarrier sinusoidal pulse-width modulation (MCSPWM) for switching control have commonly been integrated together. However, these conventional approaches do not directly address the issue of unequal switching. Hence, in this work, effort is performed to allow each individual H-bridge module to operate with balance switching pattern, by evenly distributing the PWM switching signal to them. Design concept of the proposed method is modeled in MATLAB-Simulink platform. To critically assess its effectiveness, comparative analysis involving two types of highly nonlinear rectifier loads and distorted grid is performed. The presented simulation findings confirmed effectiveness of the proposed method in maintaining voltage balance of the 5-level CHB inverter when mitigating harmonics under adverse grid.

Analysis of Cascaded Asymmetric Inverters using Low Frequency Technique

Multilevel inverters include a wide range of configurations and numerous benefits. Since each level switching angle is not neatly prepared, most conventional inverters cannot produce optimized waveforms. To attain an adequate voltage profile, we should indeed closely review the switching angle arrangement to attain a minimal Total Harmonic Distortion (THD). This work focuses on Cascaded H Bridge (CHB) multilevel inverters with asymmetrical configuration operating under a low frequency (LF) scheme. This work discusses various methods of harmonic mitigation techniques that comes under the LF scheme which includes the finest switching angle optimizations for generating various levels. Furthermore, the effectiveness of the topologies is investigated by minimizing lower-order harmonics and THD. THD is compared for various mitigation techniques for seven and nine-level configurations. The proposed configurations are simulated by employing MATLAB/Simulink. THD is calculated theoretically and evaluated by comparing it to simulated results for the suggested inverters. Additionally, thermal simulations of the configuration are carried out in PLECS to estimate power losses and efficiency. The suggested configurations are examined utilizing OPAL-RT (4510) test bed and the outcomes are included.

Multilevel inverter: harmonic analysis with and without filters for RL load using SPWM techniques

Multilevel inverter (MLI) gains more attraction compared to conventional inverter as it generates a staircase output voltage that mimics sine waves of desired output voltage. Cascaded H-bridge (CHB) topology is taken into consideration owing to several benefits over conventional inverters. Various levels of CHB (3 and 5 level) inverters are compared on diverse parameters. In this paper level shift sinusoidal pulse width modulation technique is considered resulting in reduced lower order harmonic (LOH) distortion and improve the quality of output current and voltage depending on the load. Since, the LOH are too dangerous for power electronic circuits. An attempt to shift all the LOH above 50th order depending on the modulation technique with analogy for selecting an appropriate switching frequency is highlighted. The effect of change in switching frequency and modulation index (MI) on RMS output voltage, % voltage total harmonic distortion (VTHD), output power factor with different modulation techniques such as phase disposition pulse width modulation (PsD PWM), phase opposite disposition (POD PWM), alternative phase opposition disposition (APOD PWM) is portrayed in the paper. Further, to boost the performance a unique filter circuits with optimal design values of Inductance and capacitance driven with IEEE 519-2022 standards. The effectiveness in terms of with and without filter is verified and validated using MATLAB.

Minimum Voltage Operation of Cascaded H-Bridge StatComs Using Discontinuous Modulation

Minimum Voltage Operation of Cascaded H-Bridge StatComs Using Discontinuous Modulation