Full Inverter Research Articles

Design of a Single Phase HERIC-SPWM

Development in the field of technology has experienced rapid development in recent years, especially in inverter. Every year the development of inverters is very fast starting from full bidge inverters to HERIC inverters, inverters are usually used to convert DC voltage to AC, HERIC inverters are modifications of full bidge inverters with 2 additional IGBTs on the output side, therefore this paper will discuss about inverter design. HERIC SPWM 1 phase.The HERIC inverter will be compared with full bridge inverters to find out the advantages of these modifications. The modulation technique here uses SPWM (sinusoidal pulse width modulation) modulation technique as the switching process. IGBT switching on the HERIC inverter to produce the desired output waveform. The methodology for making a 1-phase HERIC SPWM inverter using a source from the PLN road network which will then be rectified by the rectifier. The rectifier output of 311 vdc will then be converted into AC voltage with output by the HERIC inverter.So that by making this single-phase HERIC SPWM inverter it is possible to be efficient and produce the power supply that will be used.

Level-Shift PWM Control of a Single-Phase Full H-Bridge Inverter for Grid Interconnection, Applied to Ocean Current Power Generation

A small prototype of a 5-level single-phase full H-bridge inverter for ocean current applications is presented. The inverter was designed applying level-shift control in pulse-width modulation (LS-PWM), and experimental tests were conducted using a variety of modulation subschemes, including in-phase disposition (IPD), alternate-phase opposition–disposition (APOD), and phase opposition–disposition (POD). The test results were examined for harmonic content and voltage total harmonic distortion (THDV). The results suggest that the inverter presents a viable solution with significant potential for the development of a larger three-phase inverter model that can be used to connect ocean current power sources to the electrical grid.

Parabola‐trapezoid and staircase current supply methods for PMBLM with full inverter utility and reduced torque ripple

The permanent magnet brushless motors (PMBLM) are utilised extensively in many high-performance applications where smoothness of output torque is necessary. When driven with conventional square-wave current, the PMBLM is hard to make full use of inverter capacity because of short current supply time. Besides, it is hard to produce smooth output torque because the phase inductances slow down the desired step response of the phase current seriously. Although the sinusoidal-wave current changes continuously, there exists a fixed-frequency torque ripple for trapezoid back-electromotive force motor. To solve the problems, two novel current supply methods, called as staircase waveform and parabola-trapezoid waveform, are proposed in this study. With the same phase current magnitude as square waveform, the staircase waveform can output two times torque with low-resolution position sensors. The parabola-trapezoid supply method can further improve the smoothness of doubled output torque by unique parabolic rising and falling edge waveform design, while a high-resolution position sensor is needed. Simulation and experimental tests of four different current supply methods are given to corroborate the effectiveness of the proposed method in inverter utility and torque ripple reduction.

Fast and Easily Implementable Detection Circuits for Short Circuits of Power Semiconductors

Short-circuit detection is a fundamental function of most inverters. In this paper, two new fast and easily implementable short-circuit detection approaches are presented. The first one offers a significantly accelerated desaturation detection. The second one allows a full inverter to be protected by only one short-circuit detection circuit. Both approaches are verified by simulations and hardware tests.

Realization of single-phase single-stage grid-connected PV system

This paper presents a single phase single stage grid-tied PV system. Grid angle detection is introduced to allow operation at any arbitrary power factor but unity power factor is chosen to utilize the full inverter capacity. The system ensures MPPT using the incremental conductance method and it can track the changes in insolation level without oscillations. A PI voltage controller and a dead-beat current controller are used to ensure high quality injected current to the grid. The paper investigates the system structure and performance through numerical simulation using Matlab/Simulink. An experimental setup controlled by the MicrolabBox DSP prototyping platform is utilized to realize the system and study its performance. The precautions for smooth and safe system operation including the startup sequence are fully considered in the implementation.

All-Oxide Inverters Based on ZnO Channel JFETs With Amorphous ZnCo<sub>2</sub>O<sub>4</sub> Gates

We present integrated inverter circuits based on junction FETs (JFETs) with ZnO channels and amorphous ZnCo2O4 gate contacts. The inverters reach high gain values up to 276 and uncertainty ranges down to 0.3 V for an operating voltage of 3 V. The magnitude of the gain is traced back theoretically to the slope of the JFET saturation current. The use of a level shifter is demonstrated, in order to obtain full inverters, which can be integrated into logic circuits.

A Novel Three-Level Hysteresis Current Regulation Strategy for Three-Phase Three-Level Inverters

This paper presents a new hysteresis current regulation strategy for the neutral point clamped and flying capacitor (FC) three-level inverters. The strategy uses the measured average of the switched phase leg output voltage to adjust the controller hysteresis band as the load back EMF varies to maintain a near constant phase leg switching frequency. The phase leg switchings are then fine tuned to a fixed frequency clock to further improve frequency regulation. Next, the zero-crossings of the measured phase leg average voltages are used to select between positive and negative switched output voltage levels, so that only one hysteresis current regulator is required for the full inverter switched output voltage range. For the FC inverter, a state machine is then added to select between redundant switching states to maintain balanced capacitor voltages. Finally, the controller is extended to a three-phase system by subtracting the common mode interacting current from the total phase leg current error before making any switching decision. The resulting controller achieves a line-to-line harmonic performance that is very close to open-loop phase disposition pulse width modulation, while retaining all of the dynamic benefits of hysteresis current regulation.

FCS-MPC-Based Current Control of a Five-Phase Induction Motor and its Comparison with PI-PWM Control

This paper presents an investigation of the finite-control-set model predictive control (FCS-MPC) of a five-phase induction motor drive. Specifically, performance with regard to different selections of inverter switching states is investigated. The motor is operated under rotor flux orientation, and both flux/torque producing (d-q) and nonflux/torque producing (x-y) currents are included into the quadratic cost function. The performance is evaluated on the basis of the primary plane, secondary plane, and phase (average) current ripples, across the full inverter's linear operating region under constant flux-torque operation. A secondary plane current ripple weighting factor is added in the cost function, and its impact on all the studied schemes is evaluated. Guidelines for the best switching state set and weighting factor selections are thus established. All the considerations are accompanied with both simulation and experimental results, which are further compared with the steady-state and transient performance of a proportional-integral pulsewidth modulation (PI-PWM)-based current control scheme. While a better transient performance is obtained with FCS-MPC, steady-state performance is always superior with PI-PWM control. It is argued that this is inevitable in multiphase drives in general, due to the existence of nonflux/torque producing current components.

Electric Control Substituting Pitch Control for Large Wind Turbines

A completely electrical control of a variable speed wind turbine is experimentally verified. A vertical axis wind turbine with a direct driven generator and an electrical system with diode rectification and full inverter connected to the electric grid is presented. This is the first paper that presents this novel 200 kW wind power plant erected at the west coast of Sweden. The turbine has fixed pitch and is only controlled electrically accommodated by passive stall of the blades. By electrically controlling the generator rotational speed with the inverter, passive stall regulation is enabled. The first results on experimental verification of stall regulation in gusty wind speeds are presented. The experiments show that the control system can keep the turbine rotational speed constant even at very gusty winds. It is concluded that electrical control accommodated by passive stall is sufficient as control of the wind turbine even at high wind speeds and can substitute mechanical control such as blade pitch.

Study of Three-Phase Full Bridge Spwm VSI

In order to reveals the dynamic, nonlinear work process of three-phase SPWM inverter, simulation model of three-phase full bridge voltage source SPWM inverter was built. Typical figure of voltage, current and spectrum was given and analyzed. Figures include line voltage of load, phase voltage of load, neutral point voltage of load, source current wave, Fourier analysis, Total Harmonic Distortion of voltage and current, inverter input impedance, line to line impedance. This Simulation model and results can be used as auxiliary in teaching, scientific research and product development. This simulation model was intuitive, commutative, being able to display graphs dynamically. Using this simulation model in class, the difficult in teaching three-phase full bridge SPWM inverter will be solved, it can also advance students’ studying interests and strengthen their understanding and save class hours. This simulation model has important value.

Direct Flux Field-Oriented Control of IPM Drives With Variable DC Link in the Field-Weakening Region

This paper presents the direct flux control of an interior permanent-magnet (IPM) motor drive in the field-weakening region. The output torque is regulated by the coordinated control of the stator flux amplitude and the current component in quadrature with the flux, and it is implemented in the stator flux reference frame. The control system guarantees maximum torque production taking into account voltage and current limits, in particular in case of large dc-link variations. The field-oriented control does not necessarily require an accurate magnetic model of the IPM motor, and it is able to exploit the full inverter voltage at different dc-link levels with no additional voltage control loop. The feasibility of the proposed control method is investigated in discrete-time simulation, then tested on a laboratory rig, and finally implemented on board of an electric scooter prototype. The motor under test is an IPM permanent-magnet-assisted synchronous reluctance machine, with high-saliency and limited permanent-magnet flux.

Electron Irradiation Lifetime Control for SiC Bipolar Devices of 200 kVA High Power SiC Inverters

To reduce the switching power losses of SiC bipolar devices, an electron irradiation lifetime control method was investigated and was successfully applied to the development of 200kVA full SiC inverters, in which SiCGTs and SiC pn diodes irradiated electrons were used at the condition required to minimize inverter power loss.

A Digital Pulsewidth Modulator Employing Advanced Modulation Techniques

Advanced pulsewidth modulation (PWM) techniques for inverters allow the use of high-efficiency ac drives with low torque and speed pulsations and with reduced losses. A digital control scheme for a thyristor inverter is presented, where firing patterns satisfying given requirements like harmonic elimination or loss minimization have been calculated and stored in programmable read-only memory (PROM). Moreover, such a tontrol permits a continuous variation of output voltage over the modulation range for full inverter utilization. Evaluation using a 22-kW induction motor drive verified that the control provides a clean frequency spectrum over the operating range of the drive (0-100 Hz).